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

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https://hg.mozilla.org/integration/gaia-central/rev/1c09a4066131
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Merge pull request #22929 from KevinGrandon/bug_1053258_search_app_icon

Bug 1053258 - Change Search icon to Browser icon

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https://hg.mozilla.org/integration/gaia-central/rev/857404afe0a3
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Bug 1053258 - Change Search icon to Browser icon r=benfrancis
Bumping manifests a=b2g-bump