Fix mouse exploration on Windows Terminal (#20450)
Closes #20448
Summary of the issue:
Mouse exploration doesn't work on Windows Terminal due to the window hierarchy.
Description of user facing changes:
Hovering the mouse over a Windows Terminal window now reports the text (the whole line by default). Controls of the tab bar and scrollbars also work.
Description of developer facing changes:
Adds a dedicated app module for this application as well as a new TextRange class to make sure hovering over a window doesn't try to report the entire text buffer.
Description of development approach:
Testing strategy:
Opened a Windows Terminal window and moved the mouse around. Also tried with an instance with a large buffer.
