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

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https://hg.mozilla.org/integration/gaia-central/rev/c53fa62cb8c5
Author: Zac <zcampbell@mozilla.com>
Desc: Merge pull request #23467 from chirarobert/update_browser_stuff

Bug 1059245 - Update tests and framework to use the new Browser app

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https://hg.mozilla.org/integration/gaia-central/rev/c8c3b0eb2a75
Author: Robert Chira <robertchira@P5075.(none)>
Desc: Bug 1059245 - Update tests and framework to use the new Browser app
Bumping manifests a=b2g-bump