Make internal comments the default for comments in transitions

This ticket was created to follow up on this ticket (JSDSERVER-1733) which has been solved in the new issue view where:

• The comment box requires you to select "Add internal note" or "Reply to customer", which means there is no default for clickthrough navigation to commenting

However, this has not yet been solved for transition screen comments so this ticket will capture that requirement. The need is to make sure that agents don't accidentally share comments with customers unwittingly due to being unfamiliar with the tool.