Fix: Target AT Translated keyboard for Nitro button and prevent GUI spam

[VinciyS]

What does this PR do?

Thıs PR fixes two major issues in the MapNitroButton.sh script that prevented the Nitro button from launching the application on modern Acer devices (tested on Acer Nitro 16).

Root Causes & Fixes:

1. Wrong Device Targeting: The original script used a generic grep "keyboard\|Keyboard" which often targets external USB receivers or virtual Video Buses instead of the actual motherboard matrix where the Nitro button is hardwired.
   • Fix: Narrowed the grep target specifically to "AT Translated Set 2 keyboard".
2. Privilege Drop / Spam Issue: The script struggled with privilege drops and would spawn multiple instances of the application if the button was pressed consecutively.
   • Fix: Simplified the execution flow by only elevating evtest via sudo while keeping the rest in user-space. Added a pgrep check to prevent GUI spamming if the application is already running.

Testing:

• Tested on acer nitro 16.
• The button now successfully intercepts code 425 on the correct event node and launches the GUI without duplicate instances.
• I dont know if this works on other Acer devices so let me know if it doesnt work