Add the attachment insert button to the Assign issue dialog

Problem Definition

Currently, the assign issue dialog does not have the attachment insert button if there are no attachments in the issue. If there are attachments in the issue, users would not be able to add new attachments and could only select attachments which are already on the issue.

Suggested Solution

Add the attachment insert button with the capability to add new attachments to the issue.

Why this is important

Simplify actions by using one dialog, a user can assign, add comments with attachments and also reduces the number of email notification to the affected users.

Workaround

Add the attachment to the issue first, then assign the issue.