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

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https://hg.mozilla.org/integration/gaia-2_0/rev/c073ba17f080
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Merge pull request #25146 from etiennesegonzac/bug-1073807-2.0

Bug 1073807 - [2.0 only] Improve smoothness of utility tray r=cwiis

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https://hg.mozilla.org/integration/gaia-2_0/rev/288f80ef8df1
Author: Alexandre Lissy <lissyx+github@lissyx.dyndns.org>
Desc: Bug 1073807 - [2.0 only] Improve smoothness of utility tray
Bumping manifests a=b2g-bump