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

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https://hg.mozilla.org/integration/gaia-central/rev/4ccffd205a31
Author: John Hu <johu@mozilla.com>
Desc: Merge pull request #12660 from mahsam/882088-video-thumbnail

882088 - fix thumbnail aspect ratio in video app, r=johnhu

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https://hg.mozilla.org/integration/gaia-central/rev/4d6cb187e5e4
Author: mahsam <mahsam.29@gmail.com>
Desc: 882088 - fix thumbnail aspect ratio in video app

882088 - better calculation for square images

882088 - use scale function in order to fix 1 pixel issue

882088 - add some comments