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

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https://hg.mozilla.org/integration/gaia-central/rev/9d24e9cd5d1f
Author: David Flanagan <dflanagan@mozilla.com>
Desc: Merge pull request #12715 from es92/music2update3

Music2: UI + Feature Update r=davidflanagan

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https://hg.mozilla.org/integration/gaia-central/rev/e87e15f5e8f5
Author: Evan Shapiro <evan.a.shapiro@gmail.com>
Desc: Music2: UI + Feature Update