If it comes back to a prompt (as yours appears to be doing), it finished successfully. If not, and you have to break out of it to do anything, then something is amiss.
Updating MYSQL is the final step, but there's no end message. A request has been made to add an "Update Complete" message to the script.
If it isn't coming back to a prompt, then there are ways to remedy it. One drastic method is to delete the workspace and create a new one. Be sure to select the cs50 template when you do.
Also, very important: be sure to back up all your work and files before deleting the workspace so that you can put them back later.
If this answers your question, please click on the check mark to accept. Let's keep up on forum maintenance. ;-)
Or, it seems there really was a bug in update50, which will be fixed shortly. (4/10/18)