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

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https://hg.mozilla.org/integration/gaia-central/rev/11509e58720a
Author: Sam Foster <sam@sam-i-am.com>
Desc: Merge pull request #20995 from sfoster/bug-1023179-tutorial-tests

Bug 1023179  - Fix FTU video unloading/loading, r=fcampo

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https://hg.mozilla.org/integration/gaia-central/rev/7f3fb9e85165
Author: Sam Foster <sfoster@mozilla.com>
Desc: Bug 1023179  - Fix FTU video unloading/loading, refactor tutorial initialization. r=fcampo
Bumping manifests a=b2g-bump