Bumping gaia.json for 4 gaia-central revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/53dfeba0961f
Author: John Hu <johu@mozilla.com>
Desc: Merge pull request #12852 from huchengtw-moz/wallpaper/Bug_922400_cannot_set_wallpaper

Bug 922400 - [gallery][homescreen][helix] cannot set wallpaper from gall..., r=djf

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https://hg.mozilla.org/integration/gaia-central/rev/739f4dc6c341
Author: John Hu <johu@mozilla.com>
Desc: Bug 922400 - [gallery][homescreen][helix] cannot set wallpaper from gallery

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https://hg.mozilla.org/integration/gaia-central/rev/fb933379598f
Author: Fernando Campo <fernando.campo@o2.com>
Desc: Merge pull request #12941 from flodolo/bug927766

Bug 927766: FTE, fix hidden network settings localizability (r=fcampo)

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https://hg.mozilla.org/integration/gaia-central/rev/9351815cd108
Author: Francesco Lodolo <flod@lodolo.net>
Desc: Bug 927766: FTE, fix hidden network settings localizability

Add data-l10n-ide to the existing button, make all options for security
localizable