Remove operations_feature_flags_clients.token column

What does this MR do?

This MR removes operations_feature_flags_clients.token column. It was ignored in %12.5 (!18923 (merged)).

Screenshots

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.
• [-] Tested in all supported browsers

Related to #35697 (closed).