Add unit tests for RadioButton and RadioButton.RadioButtonAccessibleObject

[Olina-Zhang]

Related https://github.com/dotnet/winforms/issues/10453

Proposed changes

• Add unit test for RadioButton to test its property: CheckAlign

• Add unit test for RadioButton.RadioButtonAccessibleObject to test its properties: Name, KeyboardShortcut

  Microsoft Reviewers: Open in CodeFlow

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 74.65341%. Comparing base (bb601b3) to head (26a652c). Report is 5 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #11687 +/- ## =================================================== + Coverage 74.65248% 74.65341% +0.00092% =================================================== Files 3042 3042 Lines 629821 629852 +31 Branches 46847 46846 -1 =================================================== + Hits 470177 470206 +29 - Misses 156275 156280 +5 + Partials 3369 3366 -3 ``` | [Flag](https://app.codecov.io/gh/dotnet/winforms/pull/11687/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=dotnet) | Coverage Δ | | |---|---|---| | [Debug](https://app.codecov.io/gh/dotnet/winforms/pull/11687/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=dotnet) | `74.65341% <100.00000%> (+0.00092%)` | :arrow_up: | | [integration](https://app.codecov.io/gh/dotnet/winforms/pull/11687/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=dotnet) | `17.95959% <ø> (+0.01043%)` | :arrow_up: | | [production](https://app.codecov.io/gh/dotnet/winforms/pull/11687/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=dotnet) | `47.64094% <ø> (-0.00346%)` | :arrow_down: | | [test](https://app.codecov.io/gh/dotnet/winforms/pull/11687/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=dotnet) | `96.97864% <100.00000%> (+0.00039%)` | :arrow_up: | | [unit](https://app.codecov.io/gh/dotnet/winforms/pull/11687/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=dotnet) | `44.68697% <ø> (-0.00397%)` | :arrow_down: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=dotnet#carryforward-flags-in-the-pull-request-comment) to find out more.