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

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https://hg.mozilla.org/integration/gaia-central/rev/4615d17d8707
Author: Aleh Zasypkin <aleh.zasypkin@gmail.com>
Desc: Merge pull request #25882 from azasypkin/bug-1094822-thread-header-ltr

Bug 1094822 - [Messages][RTL] Number of group thread participants in Thread panel heading should always be LTR. r=julien

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https://hg.mozilla.org/integration/gaia-central/rev/56e67cc488cc
Author: Aleh Zasypkin <azasypkin@mozilla.com>
Desc: Bug 1094822 - [Messages][RTL] Number of group thread participants in Thread panel heading should always be LTR. r=julien
Bumping manifests a=b2g-bump