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

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https://hg.mozilla.org/integration/gaia-central/rev/b7d74d7ca307
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Merge pull request #22936 from KevinGrandon/bug_1054439_system_rename_notification_test

Bug 1054439 - [System] Fix notification launch app test path

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https://hg.mozilla.org/integration/gaia-central/rev/dc8f0f1b4697
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Bug 1054439 - [System] Fix notification launch app test path r=me
Bumping manifests a=b2g-bump