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

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https://hg.mozilla.org/integration/gaia-central/rev/4bbc9f71b0e3
Author: Arnau <arnau@arnaumarch.com>
Desc: Merge pull request #13134 from rnowm/931693

Bug 931693 - Confirm [BB] - Fix console warning due to flex property

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https://hg.mozilla.org/integration/gaia-central/rev/81d3ebe3d0a0
Author: rnowm <arnau@arnaumarch.com>
Desc: Bug 931693 - Confirm [BB] - Fix console warning due to flex property