CI: Update CEF version to 4638 (Chromium 95) on all platforms

[WizardCM]

Description

This updates the obs-browser dependency CEF to Chrome 95, released November 2021 on all platforms, including Flatpak.

Known issues (likely to be race conditions):

1. Linux: a (random) shutdown crash when a browser source or panel is open
2. Linux: a (reproducible) shutdown crash when a browser source is open (verifiable with Twitch specifically, but not the default url)
3. Linux: a (reproducible) crash fixed by obsproject/obs-browser@f743194

The macOS & Windows builds include shared texture support, and additionally all platforms include a new API (currently unused) to provide per-source permission control for microphones, webcams & display capture.

Motivation and Context

Outdated CEF is bad for various reasons. Users also ask for features unavailable in the current versions provided.

This update additionally fixes a stutter/crackle that users occasionally hear through the "Control audio via OBS" checkbox.

How Has This Been Tested?

Built on CI, launched on Windows, macOS & Linux (via Flatpak).

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Performance enhancement (non-breaking change which improves efficiency)

Checklist:

• My code has been run through clang-format.
• I have read the contributing document.
• My code is not on the master branch.
• The code has been tested.
• All commit messages are properly formatted and commits squashed where appropriate.
• I have included updates to all appropriate documentation.

[GeorgesStavracas]

Thanks for updating the Flatpak file together with the Linux job. Known crashes aside, I think the Linux changes of this PR look good.