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

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https://hg.mozilla.org/integration/gaia-central/rev/83c05c18c3b1
Author: Arnau <arnau@arnaumarch.com>
Desc: Merge pull request #19265 from rnowm/1009450

Bug 1009450 - [Messages] "X" icon lost when accessing to Messages Settings screen r=arthurcc

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https://hg.mozilla.org/integration/gaia-central/rev/f561ee1d6c44
Author: rnowm <arnau@arnaumarch.com>
Desc: Bug 1009450 - [Messages] "X" icon lost when accessing to Messages Settings screen
Bumping manifests a=b2g-bump