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

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https://hg.mozilla.org/integration/gaia-central/rev/d10b41974fe0
Author: David Flanagan <dflanagan@mozilla.com>
Desc: Merge pull request #12409 from davidflanagan/bug878057

Bug 878057: allow songs to be picked as ringtones

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https://hg.mozilla.org/integration/gaia-central/rev/24d64e46a9a2
Author: David Flanagan <dflanagan@mozilla.com>
Desc: Bug 878057: allow songs to be picked as ringtones