Web service tokens should be read-once

Behat test 1. Run the Behat feature: mdk behat -r -n "Manage external services tokens" 2. Verify that all scenarios and steps are passed without any failures.   Manual test Login as admin. Navigate to  Site Administration -> Server -> Web services -> Manage tokens. Verify that you will not see the Token column anymore. Verify that you will see the Name column. Click Create token. Verify that you will see a new field called Name. Verify that the Valid until will be enabled by default. Verify that the default value of Valid until is the next month (30 days from now). Fill the name as: Test token. Try to create the token. Verify that you will see a message: Copy the token now. It won't be shown again once you leave this page. Verify that you will see the new token. Verify that you will see a button called Copy to clipboard Click on the Copy to clipboard button. Verify that you will see a toast: Text copied to clipboard. Verify that the token value will be copied to your clipboard. Refresh the page. Verify that you will not see the Copy to clipboard button anymore. Verify that you will not see the token value anymore. Click Create token button. Leave the Name as blank. Try to create the token. Verify that the newly created token name has the following format: Webservice- [5 random characters] . Privacy Login as admin. Navigate to  Site Administration -> User -> Privacy and policies -> Plugin privacy registry. Expand core -> core_external Verify that you will see a field called name in external_tokens table. Verify that the description of that field is: The token name