Feature: Support changing behavior of buttons with modifier keys

[hishitetsu]

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.
  Closes Feature: Change the behavior of toolbar and flyout buttons with modifier keys #12117

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 remove any strings from the en-us resource file?
  • Did you search the solution to see if the string is still being used?
• Did you implement any design changes to an existing feature?
  • Was this change approved?
• Are there any other steps that were used to validate these changes?
  1. Holding down Shift and pressing the delete button on the toolbar or flyout will result in permanent deletion.
  2. Holding down Shift and pressing the paste button on the toolbar will paste items into selected folder. If no items are selected, it will act as normal pasting.

[QuaintMako]

Some feedback about the code. I cannot test it though. Some interesting feature that might be very powerful on the long run.

To be honest fully, there is a little something feeling wrong to me but I cannot pinpoint what... I'll be sure to come back to elaborate when I have IDE to review it properly.

[QuaintMako]

I cannot test the code, yet with the suggested refactoring done, I trust the concept way more!

LGTM, I'll need someone else to test the code.