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

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https://hg.mozilla.org/integration/gaia-central/rev/0f502dfafd72
Author: Ben Francis <ben@tola.me.uk>
Desc: Merge pull request #11577 from daleharvey/839194

Bug 839194 - Make prompts consistent between system and browser

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https://hg.mozilla.org/integration/gaia-central/rev/54596a711b4a
Author: Dale Harvey <dale@arandomurl.com>
Desc: Bug 839194 - Make prompts consistent between system and browser