"Add to issue only" option when editing an external comment sets the comment to internal

Summary

When editing an external comment (for instance to correct the spelling of a comment) there are 2 options available:

1. Share with Customer
2. Add to issue only
   The second option creates the impression that the edit of the comment will only result in the edit taking place, and no notification event to be triggered, whereas the share with customer option created the impression this will trigger a notification event towards the customer.
   Instead, when the add to issue only option is being used, the external comment will be set to internal upon saving

   Steps to Reproduce

3. Create a Service Desk
4. Raise a request on behalf of a customer
5. Add a comment to the request
6. Edit the comment from step 3 and choose "add to issue only"

Expected Results

The comment gets edited, and no notification gets triggered. The comment remains visible for the customer.

Actual Results

The comment gets edited, and no notification gets triggered. The comment changes from external to internal and as such will not be visible for the customer anymore