vmmanager:revert gpu logging

[F0bes]

Description of Changes

Rationale behind Changes

Suggested Testing Steps

[stenzek]

Just taking the additional issues on here, since it was missed in the original PR:

1. You can't assume the presence of glxinfo, Ubuntu systems don't have it installed by default.
2. glxinfo creates a GL context, which is going to power up discrete GPUs if it's e.g. overridden via an environment variable, resulting in several seconds delay on startup.
3. /etc/os-release is going to be meaningless when running in a flatpak, because it's the container/runtime environment, and you can't access the host.
4. Mac wasn't considered in GPU logging.

If it's part of a support request, then ehh, whatever, but otherwise the GS startup (which we already log) is a more accurate source of truth, since that's going to show the driver version, etc.