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

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https://hg.mozilla.org/integration/gaia-central/rev/2f4376746379
Author: Ben Francis <ben@tola.me.uk>
Desc: Merge pull request #10519 from daleharvey/862579

Bug 862579 - Dont open a new tab on url activity if not needed r=benfrancis

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https://hg.mozilla.org/integration/gaia-central/rev/4ba7cba1ebda
Author: Dale Harvey <dale@arandomurl.com>
Desc: Bug 862579 - Dont open a new tab on url activity if not needed