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

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https://hg.mozilla.org/integration/gaia-2_0/rev/b692eb904b97
Author: Sergi Mansilla <sergi.mansilla@gmail.com>
Desc: Merge pull request #21831 from sergi/blank_screen

Bug 1038815 - Contacts can get into a 'frozen' state in some cases r=francisco
Bumping manifests a=b2g-bump