Entity browser edit does not display messages

Latest release invalidates the patch above - rerolled for 8.x-2.9.

Modified patch to display error messages only on the entity browser popup.

Rebased MR

I have removed ajax response which return on closing the model.
We are getting success message in a new popup once we save the entity and here contributor require extra effort to close the popup having success message. We are already getting error messages in a same popup hence as per my opinion to show extra popup for success message seems bad UX.

Any different suggestions or solutions are most welcome.

I had a look at the conversation above. It is better to provide widget setting to control the behavior.
I have rerolled the patch #15

re-roll patch #23 according to the latest code changes.