Geo: Remove unused BlobVerificationSecondaryService

What does this MR do?

I copied and adapted this code into VerifiableReplicator and related areas. Now that it is merged, we can remove this bit.

Related to #13981 (closed)

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• [-] Merge request performance guidelines
• Style guides
• [-] Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.