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

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https://hg.mozilla.org/integration/gaia-central/rev/f8fc825cc933
Author: John Hu <johu@mozilla.com>
Desc: Merge pull request #13374 from huchengtw-moz/gallery/Bug_934553_missing_checkbox_icon

Bug 934553 - [B2G][Gallery] Check box icon is not displayed in the Crop ..., r=djf

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https://hg.mozilla.org/integration/gaia-central/rev/4d7ac8707b5f
Author: John Hu <johu@mozilla.com>
Desc: Bug 934553 - [B2G][Gallery] Check box icon is not displayed in the Crop screen when adding Gallery picture to a contact or to MMS