Refactor into model

It’s generally an antipattern for the view layer code to be calling the
API client directly.

app/main/views/webauthn_credentials.py

@@ -52,9 +52,7 @@ def webauthn_complete_register():
         current_app.logger.info(f'User {current_user.id} could not register a new webauthn token - {e}')
         return cbor.encode(str(e)), 400
 
-    user_api_client.create_webauthn_credential_for_user(
-        current_user.id, credential
-    )
+    current_user.create_webauthn_credential(credential)
 
     flash((
         'Registration complete. Next time you sign in to Notify '

app/models/user.py

@@ -360,6 +360,11 @@ class User(JSONModel, UserMixin):
             for credential in self.webauthn_credentials
         ]
 
+    def create_webauthn_credential(self, credential):
+        user_api_client.create_webauthn_credential_for_user(
+            self.id, credential
+        )
+
     def serialize(self):
         dct = {
             "id": self.id,