Bug 1898394 - Use gecko-dev repo for Fenix and Focus Android manifests

[brennie]

Firefox 125 was the last version to use the
@mozilla-mobile/firefox-android repo. Now it is in mozilla-central, so we can use the @mozilla/gecko-dev mirror. Unfortunately, gecko-dev does not have tagged releases, so we cannot look up manifests by their version and have to use --ref instead.

Additionally, we were looking for Fenix manifests in the @mozilla-mobile/fenix repo for version < 110. However, v110 was released from the fenix repo and v111 was the first version to use the combnined @mozilla-mobile/firefox-android repo. This has been updated.

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• Breaking changes: This PR follows our breaking change policy
  • This PR follows the breaking change policy:
    • This PR has no breaking API changes, or
    • There are corresponding PRs for our consumer applications that resolve the breaking changes and have been approved
• Quality: This PR builds and tests run cleanly
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• Tests: This PR includes thorough tests or an explanation of why it does not
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Branch builds: add [firefox-android: branch-name] to the PR title.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 77.41935% with 7 lines in your changes missing coverage. Please review.

Project coverage is 22.66%. Comparing base (c3774b2) to head (f2a103a).

Files	Patch %	Lines
components/support/nimbus-cli/src/config.rs	63.15%	7 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6347      +/-   ##
==========================================
+ Coverage   22.63%   22.66%   +0.02%     
==========================================
  Files         333      333              
  Lines       29836    29860      +24     
==========================================
+ Hits         6754     6768      +14     
- Misses      23082    23092      +10     

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[linabutler]

Looks great; thank you so much for doing this, Beth!

Losing tagged releases is a little unfortunate, but I think it's OK for now—and definitely not worth trying to rig up a separate client to fetch from hg.m.o, especially since we're planning to migrate m-c to GitHub in the not-too-distant future.