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

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https://hg.mozilla.org/integration/gaia-central/rev/147db68f9e1f
Author: Jared Hirsch <ohai@6a68.net>
Desc: Merge pull request #23222 from 6a68/bug-998464-detect-offline-during-fxa-flow

Bug 998464 - Show error if network goes offline during FxA flow. r=borja...

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https://hg.mozilla.org/integration/gaia-central/rev/f1b819e40bda
Author: Jared Hirsch <ohai@6a68.net>
Desc: Bug 998464 - Show error if network goes offline during FxA flow. r=borjasalguero
Bumping manifests a=b2g-bump