Bumping gaia.json for 1 gaia-1_3 revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-1_3/rev/4f15a88167c2
Author: Amir Nissim <amirnissim@gmail.com>
Desc: Bug 964215 - [Everything.me] Labels in Collection suggestions list do not match ones created on Homescreen [r=ranbena]