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

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https://hg.mozilla.org/integration/gaia-1_4/rev/be637b518412
Author: steveck-chung <schung@mozilla.com>
Desc: Merge pull request #17572 from steveck-chung/bug-986465

Bug 986465 - [Messaging] In list of messages to delete, contact name overlaps the photo. r=borja(cherry picked from commit 0aaacfb35bc914814904a02a49e1abb9a56ac099)
Bumping manifests a=b2g-bump