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

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https://hg.mozilla.org/integration/gaia-central/rev/b7dcf6b70431
Author: gitmai <mri@tid.es>
Desc: Merge pull request #15158 from gitmai/bug-861836-duplicate-HTML-ID

Bug 861836 - Duplicate HTML ID in Cost Control app
r=salva

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https://hg.mozilla.org/integration/gaia-central/rev/0382b7774e57
Author: mai <mri@tid.es>
Desc: Bug 861836 - Duplicate HTML ID in Cost Control app