Bumping gaia.json for 2 gaia revision(s) a=gaia-bump

========

https://hg.mozilla.org/integration/gaia-central/rev/8a7eb48c501c
Author: EragonJ <eragonj@eragonj.me>
Desc: Merge pull request #22668 from EragonJ/bug-1001285

Bug 1001285 - [meta] [Settings] Messaging Settings UX update

========

https://hg.mozilla.org/integration/gaia-central/rev/b2168251eb52
Author: EragonJ <eragonj@eragonj.me>
Desc: Bug 1001285 - [meta] [Settings] Messaging Settings UX update
Bumping manifests a=b2g-bump