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

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https://hg.mozilla.org/integration/gaia-central/rev/50199bcbdce8
Author: EragonJ (E.J.) <eragonj@eragonj.me>
Desc: Merge pull request #26910 from EragonJ/bug-1103810

Bug 1103809 - [Settings][Dialog] call_settings/voicemail should be shown...

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https://hg.mozilla.org/integration/gaia-central/rev/da4a225dbbd4
Author: EragonJ <eragonj@eragonj.me>
Desc: Bug 1103809 - [Settings][Dialog] call_settings/voicemail should be shown as a dialog
Bumping manifests a=b2g-bump