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

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https://hg.mozilla.org/integration/gaia-central/rev/6d64417c792c
Author: Min-Zhong "John" Lu <mnjul@users.noreply.github.com>
Desc: Merge pull request #22020 from mnjul/bug_1041945_lockscreen_visual_wrong

Bug 1041945 - Lockscreen notifications timestamps have wrong visual style. r=gweng

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https://hg.mozilla.org/integration/gaia-central/rev/4f4eae3ddb6a
Author: John Lu [:mnjul] <jlu@mozilla.com>
Desc: Bug 1041945 - Lockscreen notifications timestamps have wrong visual style
Bumping manifests a=b2g-bump