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

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https://hg.mozilla.org/integration/gaia-central/rev/2cc798ab1247
Author: Ryan VanderMeulen <ryanvm@gmail.com>
Desc: Merge pull request #23913 from eliperelman/bug-1064327

Bug 1064327 - Hiding SHB with fullscreen layout apps when disabled

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https://hg.mozilla.org/integration/gaia-central/rev/a7524f75c2f9
Author: Eli Perelman <eli@eliperelman.com>
Desc: Bug 1064327 - Hiding SHB with fullscreen layout apps when disabled
Bumping manifests a=b2g-bump