Wrong Notification Error Message

To reproduce:

• Log in
• Install ActivityPub extension from Extension Manager
• No additional setup
• Go to ActivityPub Dashboard or to ActivityPub Section of your own profile
• Click on follow

Expected result:

• A correct notification error message or "The user you specified cannot be found" at the bottom of viewport

Obtained Result:

• Notification error message displays "Hello World!" at the bottom of the viewport