Copied from another forum but I had the same issue and this fixed it. I found this with the same error, when trying to remove sha2 from the user profile in the workbench it would enable it straight away when I applied the changes. Once I did the below in the preferences I was then able to remove sha2 In workbench and apply it. Then ignition connected to it.
Open MySQL from System Preferences > Initialize Database >
Type your new password.
Choose 'Use legacy password'
Start the Server again.
Now connect the MySQL Workbench