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

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https://hg.mozilla.org/integration/gaia-central/rev/8379d69ea8a4
Author: Arthur Chen <crh0716@gmail.com>
Desc: Merge pull request #23609 from crh0716/1061042

Bug 1061042 - Add the icon for EU roaming r=alive

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https://hg.mozilla.org/integration/gaia-central/rev/db1e55a18c25
Author: Arthur Chen <crh0716@gmail.com>
Desc: Bug 1061042 - Add the icon for EU roaming
Bumping manifests a=b2g-bump