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

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https://hg.mozilla.org/integration/gaia-central/rev/85c753aa986c
Author: David Flanagan <dflanagan@mozilla.com>
Desc: Merge pull request #25908 from davidflanagan/bug1079519-2

Bug 1079519 - Unable to play video clips during WEBRTC video call r=russn,djf

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https://hg.mozilla.org/integration/gaia-central/rev/741213393765
Author: russnicoletti <rnicoletti@mozilla.com>
Desc: Bug 1079519 - Unable to play video clips during WEBRTC video call

Do not hide the back button under the in use overlay. Handle the case where we try to resume a video while a WebRTC call is in progress

do not hide the pick activity back button under the in-use-error overlay

use a timeupdate event instead of playing event

address review comments
Bumping manifests a=b2g-bump