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

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https://hg.mozilla.org/integration/gaia-central/rev/879e744498d2
Author: Guillaume C. Marty <gmarty@users.noreply.github.com>
Desc: Merge pull request #25186 from gmarty/Bug-1069438-Status-Bar-Play-icon-sometimes-shows-up-when-camera-in-use-icon-shown

Bug 1069438 - [Status Bar] Play icon sometimes shows up when camera in use icon is shown

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https://hg.mozilla.org/integration/gaia-central/rev/6d2a2361d54a
Author: Guillaume Marty <edo999@gmail.com>
Desc: Bug 1069438 - [Status Bar] Play icon sometimes shows up when camera in use icon is shown
Bumping manifests a=b2g-bump