Remove deprecated operations_access_level from Projects API

Background

The operations_access_level attribute was deprecated in 15.8 and scheduled for removal in 16.0, but it's still present in the API.

This came up in Create Project API not all attributes work (#335460 - closed), which reports that multiple *_access_level attributes don't function correctly in the Create Project API.

Acceptance Criteria

• Confirm current state of operations_access_level in the codebase
• Remove the deprecated field
• Determine how to handle API requests that still include operations_access_level (return an error or silently ignore?)
• Update documentation as needed