Bumping gaia.json for 3 gaia-central revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/3d9924575466
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Merge pull request #14321 from etiennesegonzac/bug-945299-call-screen-missing-transitions

Bug 945299 - Making sure we don't skip frames during the call screen opening transition.

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https://hg.mozilla.org/integration/gaia-central/rev/26444ea94dc4
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Bug 945299 - Making sure we don't skip frames during the call screen
opening transition.

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https://hg.mozilla.org/integration/gaia-central/rev/b0ec0e5ccc1f
Author: mai <mri@tid.es>
Desc: Bug 944718 - [Cost Control] Broken access to usage widget from utility tray