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

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https://hg.mozilla.org/integration/gaia-central/rev/ed483fa55e2a
Author: EragonJ <eragonj@eragonj.me>
Desc: Merge pull request #16113 from EragonJ/bug-968692

Bug 968692 - [settings] add marionette test for Screen lock panel

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https://hg.mozilla.org/integration/gaia-central/rev/4b21bb0c3dbe
Author: EragonJ <eragonj@eragonj.me>
Desc: Bug 968692 - [settings] add marionette test for Screen lock panel

- add lockscreen related test
Bumping manifests a=b2g-bump