User is not warned when completing a sprint failed or partially succeeded

Issue Summary

When completing a sprint, if the operation failed or partially succeeded, no error message is shown to the user. It gives the wrong impression that the operation was successful.

Steps to Reproduce

This is just one example scenario:

1. Create a workflow for an issue type
2. Add workflow property for a status in the workflow and restrict edit permission 

   jira.permission.edit.projectrole.<project_role> 

1. Create a sprint on the same project
2. Add issues to the sprint which are in the status from step 2
3. Try completing this sprint with a user who has Manage Sprint permission but not the project role on Step 2
4. Issues move to backlog instead of the selected next sprint, no warning/error is shown.

Expected Results

The system must either:

• not complete the sprint and warn the user that they need a specific role for this operation, or
• complete the sprint and warn the user that some steps have failed.

Actual Results

The sprint is completed. Issues moved to the backlog instead of the next sprint. The user gets no warning or error message.

Workaround

None for now.