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

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https://hg.mozilla.org/integration/gaia-central/rev/3d4a9d731e62
Author: Jared Hirsch <ohai@6a68.net>
Desc: Merge pull request #23231 from 6a68/bug-1044313-fxa-tos-zindex

Bug 1044313 - EntrySheet must be a child of #screen to get correct z-ind...

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https://hg.mozilla.org/integration/gaia-central/rev/e5f613d6b67c
Author: Jared Hirsch <ohai@6a68.net>
Desc: Bug 1044313 - EntrySheet must be a child of #screen to get correct z-index. r=alive
Bumping manifests a=b2g-bump