Added a new unassigned gesture to toggle keyboard layout

[CyrilleB79]

Link to issue number:

Closes #19211

Summary of the issue:

There was no command to toggle keyboard layout (desktop / laptop). It may be useful for testing, or for someone switching between built-in and external keyboard.

Description of user facing changes:

• Added an unassigned command to toggle keyboard layout.

Description of developer facing changes:

N/A

Description of development approach:

Added the command script in globalCommands.py.

Testing strategy:

Manual test

Known issues with pull request:

None

Code Review Checklist:

• [x] Documentation:
  • Change log entry
  • User Documentation
  • Developer / Technical Documentation
  • Context sensitive help for GUI changes
• [x] Testing:
  • Unit tests
  • System (end to end) tests
  • Manual testing
• [x] UX of all users considered:
  • Speech
  • Braille
  • Low Vision
  • Different web browsers
  • Localization in other languages / culture than English
• [x] API is compatible with existing add-ons.
• [x] Security precautions taken.