Ensure the proj route is correct for error details

What does this MR do?

Clicking on an Sentry Error via the Error tracking page will return an error to the user, due to a URL being generated incorrectly.

This fixes a bug where the URL generated would be incorrect for non-project owners.

Previous behavior:

For a project root/monitor-sandbox/error_tracking.

• When the owner visits the page: root/monitor-sandbox/error_tracking/<error_id>/details -When a user 'test' visits the page: test/monitor-sandbox/error_tracking/<error_id>/details - this URL is invalid as test/monitor-sandbox doesn't exist.

New behavior:

For a project root/monitor-sandbox/error_tracking.

• When the owner visits the page: root/monitor-sandbox/error_tracking/<error_id>/details
• When a user 'test' visits the page: root/monitor-sandbox/error_tracking/<error_id>/details - ✅

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