Remove the subject link for invitations that are not marked as spam

1. Open as Admin a clean instance of XE 7.4.2
2. Make all the configuration for the e-mail sending and invitation application to be able to send e-mails to users.
3. Go to invitation page. Type an e-mail, title, description and click the button Invite.
4. Go to your personal email and check the email content. Click on link "Decline". Confirm this action.
5. Go to page "All invitations"
6. Check for the last invitation with the status "Declined".
7. Click on subject of the invitation.

Actual result:

• When you click on subject of an invitation that has other statuses than Marked as Spam (like Declined, Failed to execute, Rescinded etc ), you are redirected to a page that gives you the option to Mark them as not Spam.
• If you continue the flow, click on "Mark as not spam" and after, click on 'Return e-mail privilege', you will get the error message: "This action cannot be carried out because all of the messages selected are of the wrong status."

Expected result:

• I expect to have in the application a checking status if the invitation is spam or not. If the invitation is with status spam, activate the redirect link to the page "Mark as not spam". If it`s not spam, deactivate the redirect and let the subject only with text in the page "All invitations". Another solution: if it`s not spam, the redirect link could be to the invitation history.
• This way, the user won`t have access to mark as not spam an invitation that is not spam and won`t get the error.