fix(gtk): Fix get scan code in GtkKeyboardInputSource

[lindexi]

PR Type

What kind of change does this PR introduce?

• Bugfix

  Now the GtkKeyboardInputSource will use the InputHelper.TryConvertKeyCodeToScanCode to convert the key code to scan code which will always return false. It means the scan code same as the key code.

  What is the new behavior?

  The GtkKeyboardInputSource will use the gtk to get the scan code

  PR Checklist

  Please check if your PR fulfills the following requirements:

  • [ ] Docs have been added/updated which fit documentation template (for bug fixes / features)
  • [ ] Unit Tests and/or UI Tests for the changes have been added (for bug fixes / features) (if applicable)
  • [ ] Validated PR Screenshots Compare Test Run results.
  • [ ] Contains NO breaking changes
  • [ ] Associated with an issue (GitHub or internal) and uses the automatic close keywords.
  • [ ] Commits must be following the Conventional Commits specification.

  Other information

  See https://docs.gtk.org/gdk3/method.Event.get_scancode.html

  Reference https://github.com/unoplatform/uno/pull/16670

  Origin commit : 98c965a794b058541cafe6756c46f021b1017d5c

  Cc @ramezgerges

  Internal Issue (If applicable):

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[Youssef1313]

/azp run

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[jeromelaban]

Thanks for your contribution!

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[lindexi]

Thank you.