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

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https://hg.mozilla.org/integration/gaia-central/rev/44808ad6508e
Author: Dominic Kuo <dkuo@mozilla.com>
Desc: Merge pull request #16114 from dominickuo/bug-958470

Bug 958470 - [Ringtones] set ringer type and use web audio api to preview the ringtones, r=jimporter

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https://hg.mozilla.org/integration/gaia-central/rev/0b3bcd148cbb
Author: Dominic Kuo <dkuo@mozilla.com>
Desc: Bug 958470 - [Ringtones] set ringer type and use web audio api to preview the ringtones
Bumping manifests a=b2g-bump