Fix #9005: Allow singular tests to be documented in properties.yml

[aranke]

Resolves #9005

Problem

Singular tests cannot be documented in YAML.

Solution

• Create a new SingularTestPatchParser to parse patches for singular tests under the data_tests key in properties.yml
  • Test that description via doc block, error_if and meta work as expected
• Add test path to source paths list so that properties.yml can be defined in the test path

Checklist

• I have read the contributing guide and understand what's expected of me.
• I have run this code in development, and it appears to resolve the stated issue.
• This PR includes tests, or tests are not required or relevant for this PR.
• This PR has no interface changes (e.g., macros, CLI, logs, JSON artifacts, config files, adapter interface, etc.) or this PR has already received feedback and approval from Product or DX.
• This PR includes type annotations for new and modified functions.

[github-actions]

Thank you for your pull request! We could not find a changelog entry for this change. For details on how to document a change, see the contributing guide.

[codecov]

Codecov Report

Attention: Patch coverage is 86.56716% with 9 lines in your changes missing coverage. Please review.

Project coverage is 88.96%. Comparing base (db69473) to head (43164f7).
Report is 7 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #10744      +/-   ##
==========================================
- Coverage   88.97%   88.96%   -0.01%     
==========================================
  Files         181      181              
  Lines       22956    23019      +63     
==========================================
+ Hits        20424    20478      +54     
- Misses       2532     2541       +9     

Flag	Coverage Δ
integration	86.14% <86.56%> (-0.01%)	⬇️
unit	62.36% <37.31%> (-0.08%)	⬇️

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

Components	Coverage Δ
Unit Tests	62.36% <37.31%> (-0.08%)	⬇️
Integration Tests	86.14% <86.56%> (-0.01%)	⬇️

[gshank]

Looks good!

[dbeatty10]

Reverted in #10790 and new PR in #10792.