Integrated Alerting: Add Pager Duty Notification Channel: after user pastes copied key Add button is not enabled

User impact:
User can not copy-paste values for Routing and Service keys.

Workaround:
Enter the value and copy-paste it.

Steps to reproduce:
Navigate to IA>>>Notification Channels tab
Click Add button to add a pager notification channel
Enter Name, choose Pager Duty from the dropdown menu
Click on the Routing key and paste some copied value to this field.

Actual result:
After the user pastes some value for the Routing Key, the Add button is still disabled.
In addition, if the user clicks on the Service key it is specified also as a required field.
Expected result:
After one of the keys is pasted or entered manually, the second field is disabled, and the Add button is enabled.