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

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https://hg.mozilla.org/integration/gaia-central/rev/4e142710052a
Author: Dominic Kuo <dkuo@mozilla.com>
Desc: Merge pull request #12378 from EragonJ/bug-876291

Bug 876291 - [Bluetooth] Change phone name screen needs to be updated to use building blocks, r=@crh0716

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https://hg.mozilla.org/integration/gaia-central/rev/53c4640b4e53
Author: EragonJ <eragonj@eragonj.me>
Desc: Bug 876291 - [Bluetooth] Change phone name screen needs to be updated to use building blocks

- use latest BB to show up prompt modal