No bug - Disable linter CI in protected branches

Merge Info

Backporting

Timeline

• Immediate: patchset needed as soon as possible
• Next Minor Stable Release: patchset that needs to be verified in nightly before backport
• Eventually: patchset that needs to be verified in alpha before backport
• No Backport (preferred): patchset for the next major stable

(Optional) Justification

I'd say let's backport it, because this problem is true also in the 13.x branchs and Mullvad Browser.

Merging

• Merge to tor-browser - !fixups to tor-browser-specific commits, new features, security backports
• Merge to base-browser - !fixups to base-browser-specific commits, new features to be shared with mullvad-browser, and security backports
  • NOTE: if your changeset includes patches to both base-browser and tor-browser please clearly label in the change description which commits should be cherry-picked to base-browser after merging

Change Description

Our CI is one of the causes of the recent Gitlab slowdowns. Although we have been able to lessen the issue, it is still not fixed.

I will be AFK in the next two weeks, so I am proposing we disable the CI so that it doesn't keep causing issues while I am away.

Since the issue seems to happen mostly for CI in protected branches -- because all jobs run at the same time -- I am only disabling it for these branches.

If it turns out keeping the MR CI is still causing issues, it should be easy enough to just go ahead and disable that as well.

Oh yeah, there is a fix for another issue that is making pipelines sometimes fail here as well... Thought it wasn't worth it to file a whole new MR just for that. Like this: https://gitlab.torproject.org/tpo/applications/tor-browser/-/jobs/637724.

How Tested

N/A

Related to #42997 (closed)