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

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https://hg.mozilla.org/integration/gaia-central/rev/9d4cf6d16100
Author: Pavel Ivanov <pivanov@mozilla.com>
Desc: Merge pull request #24113 from pivanov/bug-1061445

Bug 1061445 - Bug 1046336 - (2.1-visual-refresh) System Sound Refresh - convert sound to .wav

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https://hg.mozilla.org/integration/gaia-central/rev/4628b606ecc8
Author: Pavel Ivanov <pivanov@mozilla.com>
Desc: Bug 1061445 - Bug 1046336 - (2.1-visual-refresh) System Sound Refresh - convert sound to .wav
Bumping manifests a=b2g-bump