Bumping gaia.json for 4 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/affab69d24a0
Author: AndreiH <andrei.hutusoru@softvision.ro>
Desc: Merge pull request #16015 from gentlefolk/951159

Bug 951159 - Convert Gaia UI Tests to new notification API

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https://hg.mozilla.org/integration/gaia-central/rev/5f3f3bfb4a38
Author: gentlefolk <cemacken@gmail.com>
Desc: Bug 951159 - Convert Gaia UI Tests to new notification API

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https://hg.mozilla.org/integration/gaia-central/rev/033834b159cf
Author: Sam Joch <samuel@guiora.com>
Desc: Merge pull request #15994 from samjoch/bug-924624-UserStoryAddEdgeGesturesToFTETutorial

Bug 924624 - [User story] Add edge gestures to FTE tutorial r=arcturus

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https://hg.mozilla.org/integration/gaia-central/rev/b8fa1ae0bf18
Author: Sam Joch <samuel@guiora.com>
Desc: Bug 924624 - [User story] Add edge gestures to FTE tutorial r=arcturus
Bumping manifests a=b2g-bump