Feature: Only open single tab if user holds down ctrl + t

[ferrariofilippo]

Resolved / Related Issues

• Were these changes approved in an issue or discussion with the project maintainers? In order to prevent extra work, feature requests and changes to the codebase must be approved before the pull request will be reviewed. This prevents extra work for the contributors and maintainers.
  Related: Feature: Only execute certain actions once #11737

Changes

• I added Win key cases in OnPreviewKeyUp() to remove them from modifiers
• keyReleased ensures that the shortcut is executed only once while the key is pressed
• This PR does not address all the use cases listed in the related Feature Request, since they have not yet been implemented as RichCommands.
• I tested the behaviour of Show Preview Pane and Open New Tab

Validation
How did you test these changes?

• Did you build the app and test your changes?
• Did you check for accessibility? You can use Accessibility Insights for this.
• Did you implement any design changes to an existing feature?
  • Was this change approved?

[yaira2]

For some shortcuts, we still want users to be able to hold down on the key (eg. ctrl + tab). Can you confirm this still works?

[yaira2]

LGTM