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

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https://hg.mozilla.org/integration/gaia-central/rev/fbeb0f1b75a4
Author: Casey Yee <cyee@mozilla.com>
Desc: Merge pull request #14133 from caseyyee/bug-943822

Bug 943822 - [Building Blocks] Update edit mode BB visual design

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https://hg.mozilla.org/integration/gaia-central/rev/0319351179ca
Author: Casey Yee <casey@caseyyee.com>
Desc: Bug 943822 - [Building Blocks] Update edit mode BB visual design