Ability to choose Internal Attachment when intended to share the attachment in a public comment for customers

Problem Definition

With the new Insert an attachment already on a request feature in the new issue view, it still lacking of allowing JSM agents to share internal attachment to customer when intended to add it in a public comment.

Suggested Solution

Allow adding internal attachments to public comment.

Why this is important

This will make it easier for agents to add existing internal attachments to customers without needing to set the previous internal comment as public or reattach the file/image.