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

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https://hg.mozilla.org/integration/gaia-central/rev/b41fabfb74c1
Author: Julien Wajsberg <felash@gmail.com>
Desc: Merge pull request #14669 from julienw/950074-fix-new-message-notice

Bug 950074 - [Messages] The "you received a message" notice has a bad la...

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https://hg.mozilla.org/integration/gaia-central/rev/24cd82d6ac72
Author: Julien Wajsberg <felash@gmail.com>
Desc: Bug 950074 - [Messages] The "you received a message" notice has a bad layout r=schung

For some reason the commited CSS was wrong.
Converted it to flex box so that it looks correct also on bigger screens (like
the Peak).