Add missing data-test-subj tags for data plugin

[LDrago27]

Description

Add missing data-test-subj tags for data plugin

Issues Resolved

Screenshot

Testing the changes

Changelog

• skip

Check List

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

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 3 lines in your changes missing coverage. Please review.

Project coverage is 60.84%. Comparing base (9f23442) to head (528982a).
Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
...ta/public/ui/dataset_selector/dataset_explorer.tsx	0.00%	1 Missing ⚠️
...i/saved_query_management/saved_query_list_item.tsx	0.00%	1 Missing ⚠️
...failure_modal/shard_failure_description_header.tsx	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #9051      +/-   ##
==========================================
- Coverage   60.87%   60.84%   -0.04%     
==========================================
  Files        3808     3808              
  Lines       91209    91209              
  Branches    14410    14410              
==========================================
- Hits        55526    55492      -34     
- Misses      32142    32222      +80     
+ Partials     3541     3495      -46     

Flag	Coverage Δ
Linux_1	29.02% <0.00%> (ø)
Linux_2	?
Linux_3	37.93% <0.00%> (+<0.01%)	⬆️
Linux_4	29.01% <0.00%> (ø)
Windows_1	29.03% <0.00%> (-0.02%)	⬇️
Windows_2	56.34% <ø> (ø)
Windows_3	37.93% <0.00%> (ø)
Windows_4	29.01% <0.00%> (ø)

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