[Backport 2.x] [Discover] Display Cache Time and Clear Cache Button

[opensearch-trigger-bot]

Backport a7f3e9d from #8214.

[github-actions]

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[codecov]

Codecov Report

Attention: Patch coverage is 44.44444% with 5 lines in your changes missing coverage. Please review.

Project coverage is 61.01%. Comparing base (027bdda) to head (917fc64).
Report is 9 commits behind head on 2.x.

Files with missing lines	Patch %	Lines
...ta/public/ui/dataset_selector/dataset_explorer.tsx	0.00%	4 Missing ⚠️
...ry/query_string/dataset_service/dataset_service.ts	75.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##              2.x    #8421      +/-   ##
==========================================
- Coverage   61.01%   61.01%   -0.01%     
==========================================
  Files        3750     3750              
  Lines       89130    89139       +9     
  Branches    13922    13924       +2     
==========================================
+ Hits        54384    54386       +2     
- Misses      31371    31376       +5     
- Partials     3375     3377       +2     

Flag	Coverage Δ
Linux_1	28.86% <0.00%> (-0.01%)	⬇️
Linux_2	56.46% <0.00%> (-0.01%)	⬇️
Linux_3	37.76% <44.44%> (?)
Linux_4	30.08% <0.00%> (-0.01%)	⬇️
Windows_1	28.87% <0.00%> (-0.01%)	⬇️
Windows_2	56.41% <0.00%> (-0.01%)	⬇️
Windows_3	37.76% <44.44%> (-0.01%)	⬇️
Windows_4	30.08% <0.00%> (-0.01%)	⬇️

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