Force no site selection on /theme and /themes

[xavier-lc]

After deploying #87000, I noticed that the left side navigation appeared different on production (showing a selected site) than it did on local/PR preview (showing "All sites"), as you can see on the screenshot:

Proposed Changes

On prod, CurrentSite has a selectedSite object, whereas on local it's null, and the selectedSite prop comes from state.ui.selectedSiteId, so this PR attempts to fix that by setting the selected site to null with the noSite middleware.

Testing Instructions

1. Using an account that has more than one site, go to the PR preview link, and then to /themes?flags=-layout/dotcom-nav-redesign
2. Check that you see "All sites" at the top of the left side navigation:

Pre-merge Checklist

• Has the general commit checklist been followed? (PCYsg-hS-p2)
• https://wpcalypso.wordpress.com/devdocs/docs/testing/index.md for your changes?
• Have you tested the feature in Simple (P9HQHe-k8-p2), Atomic (P9HQHe-jW-p2), and self-hosted Jetpack sites (PCYsg-g6b-p2)?
• Have you checked for TypeScript, React or other console errors?
• Have you used memoizing on expensive computations? More info in Memoizing with create-selector and Using memoizing selectors and Our Approach to Data
• Have we added the "[Status] String Freeze" label as soon as any new strings were ready for translation (p4TIVU-5Jq-p2)?
• For changes affecting Jetpack: Have we added the "[Status] Needs Privacy Updates" label if this pull request changes what data or activity we track or use (p4TIVU-aUh-p2)?

[github-actions]

Calypso Live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-98369

Jetpack Cloud live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-98369&env=jetpack

[matticbot]

This PR does not affect the size of JS and CSS bundles shipped to the user's browser.

Generated by performance advisor bot at iscalypsofastyet.com.

[mmtr]

I noticed that the left side navigation appeared different on production (showing a selected site) than it did on local/PR preview (showing "All sites")

@xavier-lc I cannot reproduce this. Am I missing anything?

[Copons]

I noticed that the left side navigation appeared different on production (showing a selected site) than it did on local/PR preview (showing "All sites")

@xavier-lc I cannot reproduce this. Am I missing anything?

@mmtr I can repro with a clean cache (wiping the indexedDB should be enough).
Otherwise, Calypso automagically selects whatever theme I had selected before (AFAICS).

This seems to happen in every environment except dev (of course). 😭

[xavier-lc]

@mmtr could you try with different accounts? It happens to me with random testing accounts, but not the main one.

[mmtr]

@xavier-lc I've been able to reproduce it on a incognito window. But I'm unable to reproduce it locally or in Calypso Live as @Copons noted, which makes hard to verify if these changes actually solve the issue.

@xavier-lc have you managed to reproduce the issue locally? How have you determined that these changes effectively fix it?

[mmtr]

I think we can try this anyway and see what happens in prod. Code changes make sense, and they don't introduce any regression for me when I test locally

[xavier-lc]

@xavier-lc have you managed to reproduce the issue locally? How have you determined that these changes effectively fix it?

No, I haven't seen it happen locally. I just thought that the change makes sense 😅

I think we can try this anyway and see what happens in prod. Code changes make sense, and they don't introduce any regression for me when I test locally

👍

[xavier-lc]

It's working on incognito 🕵️‍♂️