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

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https://hg.mozilla.org/integration/gaia-central/rev/2304e5bee7ee
Author: Rudy Lu <me@rudy.lu>
Desc: Merge pull request #13480 from RudyLu/ftu/Bug913783-reset_keyboard_layouts

Bug 913783 - Enable language-associated keyboard layouts.
r=fcampo

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https://hg.mozilla.org/integration/gaia-central/rev/dc292dd20bb5
Author: Rudy Lu <me@rudy.lu>
Desc: Bug 913783 - Enable language-associated keyboard layouts.
 - add unit tests for layout changes