Steam for Linux requires the XTest extension

[benkibbey]

Your system information

• Steam client version (build number or date):
  Latest as of June 22
• Distribution (e.g. Ubuntu):
  Debian bookworm
• Opted into Steam client beta?: [Yes/No]
  No
• Have you checked for system updates?: [Yes/No]
  Yes
• Steam Logs: [generate by running this command in a terminal tar -zcvf ~/Desktop/steam-logs.tar.gz ~/.steam/steam/logs]
• GPU: Nvidia/Intel/AMD
  AMD

Please describe your issue in as much detail as possible:

Steam complains about the XTest extension not being available then crashes when using a PS3 controller (wired or wireless, possibly other controllers, too). Enabling the extension fixes things. This is a newer requirement that uinput and the XTest extension be enabled. Not everyone wants XTest enabled in their environment and I think there should be a way to fallback to previous input methods when there was no such requirement.

Thanks for supporting Steam on Linux!

Steps for reproducing this issue:

1. Start steam with the XTest extension disabled in the XServer configuration