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

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https://hg.mozilla.org/integration/gaia-central/rev/4560f4b17418
Author: Arthur Chen <crh0716@gmail.com>
Desc: Merge pull request #25844 from sv99/1093669

Bug 1093669 - [system] shrink_ui_test assert.deepEqual Nodes fail in newer version chai r=alive r=arthur.chen

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https://hg.mozilla.org/integration/gaia-central/rev/ffb964e314ae
Author: sv99 <sv99@inbox.ru>
Desc: Bug 1093669 - [system] shrink_ui_test assert.deepEqual Nodes fail in newer version chai
Bumping manifests a=b2g-bump