Geo: Prevent a name collision for retry_due scope

What does this MR do?

retry_due name is used in replication control flow(in ReplicableRegistry) and in legacy Geo logic. It can create name collisions at any time, but in this particular case, it was motivated by the inability to add Uploads to SSF and keeping the old logic under the feature flag. Also, verification_ prefix just makes the method name clear and consistent with what it does.

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Does this MR meet the acceptance criteria?

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