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

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https://hg.mozilla.org/integration/gaia-central/rev/91e64acd39e0
Author: Arthur Chen <crh0716@gmail.com>
Desc: Merge pull request #21490 from crh0716/1035634

Bug 1035634 - Merge the enabled layouts panel to installed keyboards panel r=eragonj

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https://hg.mozilla.org/integration/gaia-central/rev/f42c65b153de
Author: Arthur Chen <crh0716@gmail.com>
Desc: Bug 1035634 - Merge the enabled layouts panel to installed keyboards panel
Bumping manifests a=b2g-bump