Refactored the AriaLabel handling in MudCheckBox and extended it to MudRadio and MudSwitch following ARIA best practices and MudBlazor code standards.

Summary of Changes

1. MudCheckBox Refactor:

   • Removed manual aria-labelledby assignment from OnInitialized in MudCheckBox.razor.cs.
   • Moved aria-labelledby attribute assignment directly to the <input> element in MudCheckBox.razor.
   • Ensured visual labels and child content are hidden from screen readers via aria-hidden when a custom AriaLabel is provided, preventing redundant verbalization.

2. MudRadio Implementation:

   • Added AriaLabel parameter to MudRadio.razor.cs.
   • Updated MudRadio.razor to include a screen-reader-only <span> for the label and linked it to the input via aria-labelledby.
   • Applied aria-hidden to the visible label/content when AriaLabel is set.

3. MudSwitch Implementation:

   • Added AriaLabel parameter to MudSwitch.razor.cs.
   • Updated MudSwitch.razor with the same aria-labelledby and aria-hidden pattern used in the other components.

4. Testing:

   • Verified existing CheckBox_AriaLabel_OverRides tests pass.
   • Added Radio_AriaLabel test in RadioTests.cs and Switch_AriaLabel test in SwitchTests.cs.
   • Created new test components: RadioAriaLabelTest.razor and SwitchAriaLabelTest.razor.

All three components now consistently handle ARIA labels by declaring them in the Razor file and correctly managing visibility for screen readers.

Checklist:

• I've read the contribution guidelines
• My code follows the style of this project
• I've added or updated relevant unit tests