Add callout for both data explorer and legacy discover

[abbyhu2000]

Description

Add callout to inform users that legacy discover will be deprecated, and they can switch between data explorer and legacy discover.

• wait for this PR from OUI to merged so it can use the dismissible callout: Add dismissible prop to OuiCallOut oui#985
• wait for official ux wording on the callout: @KrooshalUX @vagimeli

Issues Resolved

Screenshot

Testing the changes

Check List

• All tests pass
  • yarn test:jest
  • yarn test:jest_integration
  • yarn test:ftr
• New functionality includes testing.
• New functionality has been documented.
• Update CHANGELOG.md
• Commits are signed per the DCO using --signoff

[ashwin-pc]

Suggested change

	<div>
	<EuiCallOut
	title="New Discover is available to switch by default and the old discover will be deprecated in 2.11."
	iconType="alert"
	/>
	</div>
	<EuiFlexItem grow={false}>
	<EuiCallOut
	title="New Discover is available to switch by default and the old discover will be deprecated in 2.11."
	iconType="alert"
	/>
	</EuiFlexItem>

Does this work too?

[abbyhu2000]

yes, verified and changed

[codecov]

Codecov Report

Merging #4830 (5fbf858) into feature/data-explorer (521f306) will decrease coverage by 0.15%.
Report is 12 commits behind head on feature/data-explorer.
The diff coverage is 75.72%.

@@                    Coverage Diff                    @@
##           feature/data-explorer    #4830      +/-   ##
=========================================================
- Coverage                  66.50%   66.36%   -0.15%     
=========================================================
  Files                       3289     3390     +101     
  Lines                      62821    64729    +1908     
  Branches                    9788    10306     +518     
=========================================================
+ Hits                       41782    42959    +1177     
- Misses                     18658    19234     +576     
- Partials                    2381     2536     +155     

Flag	Coverage Δ
Linux_1	34.91% <82.00%> (?)
Linux_2	55.13% <77.22%> (?)
Linux_3	43.97% <81.63%> (?)
Linux_4	35.10% <82.00%> (?)
Windows	?
Windows_1	34.92% <82.00%> (?)
Windows_2	55.10% <77.22%> (?)
Windows_3	43.97% <81.63%> (?)
Windows_4	35.11% <82.00%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
packages/osd-babel-preset/node_preset.js	100.00% <ø> (ø)
...osd-opensearch-archiver/src/lib/docs/test_stubs.ts	68.75% <ø> (ø)
...ch-archiver/src/lib/indices/create_index_stream.ts	69.76% <ø> (ø)
...ch-archiver/src/lib/indices/delete_index_stream.ts	50.00% <ø> (ø)
...ver/src/lib/indices/opensearch_dashboards_index.ts	0.00% <0.00%> (ø)
packages/osd-pm/src/utils/package_json.ts	66.66% <ø> (ø)
packages/osd-ui-shared-deps/theme.ts	41.66% <0.00%> (ø)
src/core/public/chrome/chrome_service.mock.ts	100.00% <ø> (ø)
...c/core/public/chrome/ui/header/collapsible_nav.tsx	95.45% <ø> (+0.90%)	⬆️
src/core/public/chrome/ui/header/header.tsx	75.00% <ø> (+1.66%)	⬆️
... and 37 more

... and 320 files with indirect coverage changes

[ashwin-pc]

Tagging @vagimeli cc: @mnkugler

[AMoo-Miki]

This will probably need OUI@1.3.0-beta.2 for verify.

[ashwin-pc]

@abbyhu2000 can you update the PR with the new copy and raise this against main? Also you can test the dismiss function now that OUI 1.3 beta is merged to main

[abbyhu2000]

Close this PR as #4857 contains the changes against main branch.