[File Explorer Source Control Integration] Accessibility bug fixes

[ssparach]

Summary of the pull request

This PR fixes two accessibility bugs for the File Explorer Page under Windows Customization.

References and relevant issues

https://microsoft.visualstudio.com/OS/_workitems/edit/53874018
https://microsoft.visualstudio.com/OS/_workitems/edit/53873865

Detailed description of the pull request / Additional comments

The accessibility bugs that this PR resolves are:

• On navigating to 'Unassigned' button (dropdown) or 'More options' button, narrator is not announcing position count for the list items. Arrow navigation is defined for 'Folder paths' so position count should be defined.
• On navigating to 'Unassigned' button (dropdown), narrator is announcing as 'Unassigned button collapsed' but it is not announcing its respective 'Folder path'.

Validation steps performed

Used narrator to confirm that the following expected results were achieved:

• Position count defined on navigating to the dropdown button or 'More options' button i.e. narrator announces if an item is one of two, two of four etc.
• Narrator announces the associated folder path info on navigating to dropdown button

PR checklist

• Closes #xxx
• Tests added/passed
• Documentation updated

[krschau]

Does this set the name correctly (does it sound right in Narrator / look right in acc insights/inspect) or don't you need to do the
<data name="ButtonName.[using:Microsoft.UI.Xaml.Automation]AutomationProperties.Name" xml:space="preserve"> thing in the resw file?

[ssparach]

Yes, it does seem to set the name correctly. In narrator, the path is correctly announced with backslashes, followed by the status of the drop down button. I also checked with Accessibility Insights and it did not flag any issues. Thanks!

[dhoehna]

Setting a binding for the automation name is needed when something has to change between all the items. For example, in RepoConfig. The narrator says for the edit button "Edit repository [path]" where path is different for each item.