Bumping gaia.json for 2 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/e888f7f07710
Author: James Burke <jrburke@gmail.com>
Desc: Merge pull request #23020 from jrburke/bug1037635-email-read-icons

Bug 1037635 - Implementation of new mark as read/unread icons in email app r=asuth

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https://hg.mozilla.org/integration/gaia-central/rev/c83e8c82d95a
Author: jrburke <jrburke@gmail.com>
Desc: Bug 1037635 - Implementation of new mark as read/unread icons in email app
Bumping manifests a=b2g-bump