Remove unused code

What does this MR do?

BlobUploadService doesn't call try_obtain_lease, nor should it, so this unused line should be removed.

Closes #217027 (closed)

Screenshots

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry Not needed since it is under a feature flag
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

I think tests are not needed since one would normally not expect this service to use an exclusive lease.

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