Bumping gaia.json for 1 gaia-1_2 revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-1_2/rev/7d358f92b5d7
Author: Ben Kelly <ben@wanderview.com>
Desc: Bug 939283: Revert "Merge pull request #13593 from wanderview/contacts-group-overflow"

This reverts commit 3c73873c8e8ddc8cea9665db0317785e926b286b.