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

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https://hg.mozilla.org/integration/gaia-central/rev/7ed8854b26c0
Author: Michael Henretty <michael.henretty@gmail.com>
Desc: Merge pull request #25819 from mikehenrty/bug-1090152-fix-icon-visibility

Bug 1090152 - Make sure we display statusbar icons on lockscreen even wi...

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https://hg.mozilla.org/integration/gaia-central/rev/9c649cf34014
Author: Michael Henretty <michael.henretty@gmail.com>
Desc: Bug 1090152 - Make sure we display statusbar icons on lockscreen even with fullscreen apps
Bumping manifests a=b2g-bump