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

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https://hg.mozilla.org/integration/gaia-2_1/rev/83d18920ba47
Author: Ryan VanderMeulen <ryanvm@gmail.com>
Desc: Merge pull request #26678 from etiennesegonzac/bug-1096704-2.1

Bug 1096704 - Prevent rocketbar trigger during an edge gesture.

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https://hg.mozilla.org/integration/gaia-2_1/rev/291595769506
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Bug 1096704 - Prevent rocketbar trigger during an edge gesture.

(cherry picked from commit 4d4f7b91c958f6cee8a13a4fe43c25840c142911)
Bumping manifests a=b2g-bump