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

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https://hg.mozilla.org/integration/gaia-central/rev/091d8adce0fd
Author: George <georgeiscoming@gmail.com>
Desc: Merge pull request #22821 from cctuan/1053054

Bug 1053054 - ShrinkingUI should be instantiable

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https://hg.mozilla.org/integration/gaia-central/rev/75a0de7d7b9e
Author: cctuan <georgeiscoming@gmail.com>
Desc: Bug 1053054 - ShrinkingUI should be instantiable
Bumping manifests a=b2g-bump