Add code coverage for ApplicableToButtonAttribute

[Zheng-Li01]

Related #13442

Proposed changes

Add unit test file: ApplicableToButtonAttributeTests.cs for public methods of the ApplicableToButtonAttribute.cs

Microsoft Reviewers: Open in CodeFlow

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 76.60217%. Comparing base (5821493) to head (9824fee).
Report is 5 commits behind head on main.

Additional details and impacted files

@@                 Coverage Diff                  @@
##                main      #13457          +/-   ##
====================================================
+ Coverage   62.21083%   76.60217%   +14.39134%     
====================================================
  Files           3213        3230          +17     
  Lines         638302      639102         +800     
  Branches       47201       47289          +88     
====================================================
+ Hits          397093      489566       +92473     
+ Misses        234153      145965       -88188     
+ Partials        7056        3571        -3485     

Flag	Coverage Δ
Debug	76.60217% <100.00000%> (+14.39133%)	⬆️
integration	18.78598% <ø> (-0.00281%)	⬇️
production	51.00719% <ø> (+32.21841%)	⬆️
test	97.40414% <100.00000%> (+0.00002%)	⬆️
unit	48.41383% <ø> (?)

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