Add support for ITextProvider

[chiaramooney]

Documentation

https://learn.microsoft.com/en-us/dotnet/api/system.windows.automation.provider.itextprovider?view=windowsdesktop-8.0

Behavior

Exposes methods and properties to support UI Automation client access to controls that contain text.

Controls of control type Document should always implement the ITextProvider. Controls of control type Edit or Text should conditionally support the IToggleProvider. See here for documentation.

Implementation Plan

We should:

1. Implement the ITextProvider APIs in CompositionDynamicAutomationProvider.
2. Set the list of controls who implement the ITextProvider to be Document and Edit/Text under certain conditions. To get more information on the conditions visit the page for the individual UIA control types.

For additional reference, see other provider implementations on Fabric: #11874

To Be Clarified