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

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https://hg.mozilla.org/integration/gaia-central/rev/cb68d2aeb293
Author: Ryan VanderMeulen <rvandermeulen@mozilla.com>
Desc: Merge pull request #22941 from tamarahills/bugfix/1026692v2

bug 1026692 - Access to Mute Button

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https://hg.mozilla.org/integration/gaia-central/rev/223e7bf07be9
Author: Tamara Hills <thills@mozilla.com>
Desc: bug 1026692 - Access to Mute Button.  r=rik
Bumping manifests a=b2g-bump