Add verification of commit id before calling remote

What does this MR do?

Validation of revision (commit/ref) before the call to the remote service to save network roundtrips.
This also won't produce a lot of log messages in Gitaly like revision can't contain whitespace.

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Code review guidelines
• Merge request performance guidelines
• Style guides

Availability and Testing

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