Bumping gaia.json for 1 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/63f53f21691d
Author: Ryan VanderMeulen <rvandermeulen@mozilla.com>
Desc: Revert "Merge pull request #24040 from yurenju/merge-build-apps-2"

This reverts commit 4c7473cce3910a8ac1de16f3255218cb1a9959c9, reversing
changes made to a5f97cdbddacbaea9031aa9f9f00ab74cbcb25fc.
Bumping manifests a=b2g-bump