[MeasureTool] Update default activation shortcut to resolve conflict with Windows Explorer built-in shortcut

[nx-frost]

Summary of the Pull Request

Update default activation shortcut and resolve #32623

PR Checklist

• Closes: Prefer Win-Ctrl-Shift-M instead of Windows native shortcut Win-Shift-M for Screen Ruler #32623
• Communication: I've discussed this with core contributors already. If work hasn't been agreed, this work might be rejected
• Documentation updated: If checked, please file a pull request on our docs repo and link it here: Update screen-ruler.md default activation shortcut MicrosoftDocs/windows-dev-docs#4977

Detailed Description of the Pull Request / Additional comments

The default activation shortcut for the Screen Ruler (MeasureTool) has been updated so as to no longer conflict with the built-in Windows Explorer shortcut used to restore windows minimized with ⊞ Win-M:

• Old shortcut: ⊞ Win-Shift-M
• New shortcut: ⊞ Win-Ctrl-Shift-M

Validation Steps Performed

• Installed the package on a fresh virtual machine
• Launched PowerToys
• Pressed ⊞ Win-Ctrl-Shift-M
• Observed that this caused the MeasureTool UI to appear and function normally