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

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https://hg.mozilla.org/integration/gaia-central/rev/22753dcfb99d
Author: Pavel Ivanov <pivanov@mozilla.com>
Desc: Merge pull request #13761 from pivanov/bug-938785

Bug 938785 - [Settings] App background doesn't scroll with content forcing a fullscreen layer

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https://hg.mozilla.org/integration/gaia-central/rev/24cd5f790526
Author: Pavel Ivanov <pivanov@mozilla.com>
Desc: Bug 938785 - [Settings] App background doesn't scroll with content forcing a fullscreen layer