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

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https://hg.mozilla.org/integration/gaia-central/rev/c7673349a25a
Author: gitmai <mri@tid.es>
Desc: Merge pull request #14557 from gitmai/bug-937251-CC-Remove-proxy

Bug 937251 - [Cost Control] Remove proxy
r=salva

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https://hg.mozilla.org/integration/gaia-central/rev/d1c52f81e1d1
Author: mai <mri@tid.es>
Desc: Bug 937251 - [Cost Control] Remove proxy