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ci: Repoint v2 release workflows and manifests to v1 branch
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This change repurposes all secondary v2 release workflows (cherry-pick, cut, finalize, please, publish) and Release Please manifest configs to manage legacy patch releases on the v1 branch, as v2 GA releases are now serviced directly from main.

BUG=None
TAG=agy
CONV=8876d6f0-694d-4980-9005-979adc5a2ef4

Change-Id: I9c682f5ec2c21fde95e0f00930e2442e254b33b3