Hide create issue button on vulnerability page if a customer does not have issue tracking

If the customer does not have issue tracking enabled or has a 3rd party issue tracker, then they will get the following error.

Proposal

• Hide the "Create Issue" button, if issue tracking is not turned on or a 3rd party issue tracker is in use or
• Disable the "Create Issue" button and have help text explaining that the user must have issue tracking configured to use the button.

Implementation

• hide the create issue button using the create_issue_url property if a user has the issue tracker turned off (Project -> Settings Sidebar menu -> General -> Visibility, project features, permissions -> Issues )