Fix star/bookmarking feature in Content Library

[sairina]

Summary

Description of the change(s) you made

• Added ChannelListPagination class for ChannelViewSet
• Added tests in tests_channel.py to test bookmarking feature
• Added update_from_changes method to ChannelViewSet class to override the one in UpdateModelMixin so that any user can bookmark any channel (the initial problem was that update_from_changes in UpdateModelMixin only worked with channels that a user could edit, not ones they could only view)

Manual verification steps performed

1. Log in as a non-admin user w/view-only access to a Published Channel
2. Click on the "Content Library" tab
3. Bookmark the "Published Channel" by clicking on the star icon on its card
4. After a few seconds, click on the "Starred" filter checkbox on the left-hand side under "Formats" to filter all bookmarked channels
5. Check to see that there is 1 matching result
6. Unstar "Published Channel" by clicking on the star icon on the card
7. Uncheck the "Starred" filter. Wait a few seconds
8. Click on the "Starred" filter again
9. Check to see that there are "0 results found"

Note: There is a known bug (also see below) where quick clicking on the star icon and on the "Starred" filter will yield incorrect results, and the user will have to refresh the page in order for the accurate results to occur. If this occurs, please refresh the page to see that the correct results do show up after the refresh.

Screenshots (if applicable)

Does this introduce any tech-debt items?

We will need to revisit pagination for channels.

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Reviewer guidance

How can a reviewer test these changes?

Please manually test, and note that there is an edge case where if a user bookmarks and clicks on the "Starred" filter very quickly, it will not work (they will have to refresh the page).

Fixes #2933

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Contributor's Checklist

Studio-specifc:

• Views are organized into pages, components, and layouts directories as described in the docs

Testing:

• Code is clean and well-commented
• Contributor has fully tested the PR manually
• If there are any front-end changes, before/after screenshots are included
• Critical user journeys are covered by Gherkin stories
• Any new interactions have been added to the QA Sheet
• Critical and brittle code paths are covered by unit tests

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Reviewer's Checklist

This section is for reviewers to fill out.

• Automated test coverage is satisfactory
• PR is fully functional
• PR has been tested for accessibility regressions
• External dependency files were updated if necessary (yarn and pip)
• Documentation is updated
• Contributor is in AUTHORS.md

[codecov]

Codecov Report

Merging #3070 (dd077ae) into hotfixes (28587f8) will increase coverage by 5.17%.
The diff coverage is 93.05%.

@@             Coverage Diff              @@
##           hotfixes    #3070      +/-   ##
============================================
+ Coverage     80.80%   85.97%   +5.17%     
============================================
  Files           281      304      +23     
  Lines         12659    16467    +3808     
============================================
+ Hits          10229    14158    +3929     
+ Misses         2430     2309     -121     

Impacted Files	Coverage Δ
contentcuration/contentcuration/decorators.py	56.60% <50.00%> (-37.60%)	⬇️
...ntentcuration/contentcuration/db/models/manager.py	91.05% <90.83%> (-8.95%)	⬇️
contentcuration/contentcuration/db/models/query.py	94.23% <93.75%> (-5.77%)	⬇️
contentcuration/contentcuration/forms.py	82.35% <94.04%> (+33.89%)	⬆️
contentcuration/contentcuration/api.py	92.06% <100.00%> (+1.43%)	⬆️
contentcuration/contentcuration/apps.py	100.00% <100.00%> (+11.11%)	⬆️
contentcuration/contentcuration/celery.py	90.00% <100.00%> (-1.67%)	⬇️
...tentcuration/contentcuration/context_processors.py	100.00% <100.00%> (ø)
...ontentcuration/contentcuration/db/advisory_lock.py	100.00% <100.00%> (ø)
...tcuration/contentcuration/db/models/expressions.py	95.23% <100.00%> (-4.77%)	⬇️
... and 190 more

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[rtibbles]

Code looks clean, and tests are spot on!

I need to manually test still. Also, would be good to clean up the commit history slightly!

[rtibbles]

Code looks good. Good test coverage. Manual testing showed no issues!

[pcenov]

Hi @sairina as and end user I was expecting that if the Starred filter is applied and I click the star icon to remove a starred channel, the unstarred channel will immediately disappear from the list. Currently this is not the case and it remains visible:

This is also not consistent with unstarring a channel from the Starred tab where the channel disappears immediately after having been unstarred so the question is can this be applied here as well?

[sairina]

Hi @pcenov, thank you for catching this! I didn't realize that was the expected behavior. Can you file an issue for this specific thing as a follow-up so that we can work on fixing that?

[radinamatic]

I can't recall if that was specified as the expected in original designs (cc @jtamiace & @khangmach to chime in), but ➕ for what @pcenov is suggesting: to me it also seems that more consistent user-facing behavior would be for a channel to disappear from the view when unstarred, in both the Content library (with the Starred filter on), and the Starred tabs.

[rtibbles]

I imagine it was previously unspecified - but definitely good for it to be consistent.

[khangmach]

This wasn't intentionally specified in the mocks but what ya'll are saying makes sense so I'm on board with running with this.

So when the user is..

1. under the content library tab
2. has the starred filter applied
3. sees channels appear

If they they un-star that starred channel

1. the channel should disappear from that view
2. the channel should disappear from the starred view
3. the snackbar should appear per usual