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

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https://hg.mozilla.org/integration/gaia-central/rev/2665fbf148c5
Author: gasolin <gasolin@gmail.com>
Desc: Merge pull request #13157 from gasolin/issue-932141

Bug 932141 - [Homescreen] Refactor tablet media query styles, r=crdlc

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https://hg.mozilla.org/integration/gaia-central/rev/3e8647d84744
Author: gasolin <gasolin@gmail.com>
Desc: Bug 932141 - [Homescreen] Refactor tablet media query styles