Bumping gaia.json for 1 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-2_1/rev/419cea4caf58
Author: Doug Sherk <github@sherk.me>
Desc: Bug 1079810 - Don't initialize an AudioContext on Callscreen init. r=gsvelto
Bumping manifests a=b2g-bump