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

========

https://hg.mozilla.org/integration/gaia-central/rev/a3d4eb8f484c
Author: Arnau <arnau@arnaumarch.com>
Desc: Merge pull request #16368 from nucliweb/97360-Cost-control

Fix Arrow Position

========

https://hg.mozilla.org/integration/gaia-central/rev/51173b67d02b
Author: Joan Leon <joan.leon@gmail.com>
Desc: Fix Arrow Position

Reposition the background image to fit
Bumping manifests a=b2g-bump