Bug 40763: Stop using remote localized files in CFR

Merge Info

Related Issues

• #40763 (closed)

Backport Timeline

• Immediate - patchsets for critical bug fixes or other major blocker (e.g. fixes for a 0-day exploit) OR patchsets with trivial changes which do not need testing (e.g. fixes for typos or fixes easily verified in a local developer build)
• 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 - patchset for the next major stable

Upstream Merging

• Merge to base-browser - typically for !fixups to patches in the base-browser branch, though sometimes new patches as well
  • NOTE: if your changeset includes patches to both base-browser and tor-browser please please make separate merge requests for each part

Issue Tracking

• Link resolved issues with appropriate Release Prep issue for changelog generation

Change Description

This pref change prevents Firefox from fetching TorBrowser/Data/Browser/Caches/profile.default/settings/main/ms-language-packs/asrouter.ftl, and shuts a possible error in the console (see the related issue).

I cannot get these behavior anymore, but the preference still exists, so we could just set it.