Add test coverage for TreeView

[Zheng-Li01]

related #10453

Proposed changes

• Add unit tests for TreeView to test its properties:TopNode, accessibilityObject, ItemHeight,Indent
• Add unit tests for TreeView to test its methods: ConvertTo, CollapseAll, ExpandAll, GetNodeCount, ShouldSerializeIndent, shouldSerializeItemHeightMethod, ToString

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 74.28680%. Comparing base (9f8f671) to head (2f8afe1).
Report is 3 commits behind head on main.

Additional details and impacted files

@@                 Coverage Diff                 @@
##                main      #11361         +/-   ##
===================================================
+ Coverage   74.27085%   74.28680%   +0.01595%     
===================================================
  Files           3025        3026          +1     
  Lines         626861      626966        +105     
  Branches       46742       46753         +11     
===================================================
+ Hits          465575      465753        +178     
+ Misses        157937      157868         -69     
+ Partials        3349        3345          -4     

Flag	Coverage Δ
Debug	74.28680% <100.00000%> (+0.01595%)	⬆️
integration	18.00648% <ø> (+0.01476%)	⬆️
production	47.02100% <ø> (+0.02562%)	⬆️
test	96.99508% <100.00000%> (+0.00092%)	⬆️
unit	43.99110% <ø> (+0.02106%)	⬆️

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[Tanya-Solyanik]

@Zheng-Li01 - feel free to use only the Proposed changes section in the PR description, the rest is not applicable to new test cases

[Epica3055]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[LeafShi1]

LGTM! @Tanya-Solyanik Please review this again

[Tanya-Solyanik]

Thank you!