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

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https://hg.mozilla.org/integration/gaia-2_0/rev/24b56f602e57
Author: KWierso <kwierso@gmail.com>
Desc: Revert "Merge pull request #20844 from guilherme-pg/bug1000173-tracking-notification" for gaia-unit test failures

This reverts commit 7bb5daea0f37d4371e9daa08045d45fef3b30344.
Bumping manifests a=b2g-bump