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

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https://hg.mozilla.org/integration/gaia-central/rev/efdd545d3b03
Author: Dominic Kuo <dkuo@mozilla.com>
Desc: Merge pull request #19102 from dominickuo/bug-961980

Bug 961980 - [Settings] preview the tones in the sound region when adjusting the sliders, r=crh0716

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https://hg.mozilla.org/integration/gaia-central/rev/0c01c5b7ee57
Author: Dominic Kuo <dkuo@mozilla.com>
Desc: Bug 961980 - [Settings] preview the tones in the sound region when adjusting the sliders
Bumping manifests a=b2g-bump