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

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https://hg.mozilla.org/integration/gaia-central/rev/34eecbae2a27
Author: Alive.Kuo <alegnadise@gmail.com>
Desc: Merge pull request #13113 from alivedise/bugzilla/911053/activity-window-v4

Bug 911053 - Implement ActivityWindow, r=timdream

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https://hg.mozilla.org/integration/gaia-central/rev/4c7dc2775e0b
Author: Alive Kuo <alegnadise@gmail.com>
Desc: Bug 911053 - Implement ActivityWindow