Don't set the cli attribute in the sansio scaffold

It is (currently) Flask specific and hence cannot be shared in the
sansio shared code.

src/flask/app.py

@@ -241,6 +241,16 @@ class Flask(App):
             root_path=root_path,
         )
 
+        #: The Click command group for registering CLI commands for this
+        #: object. The commands are available from the ``flask`` command
+        #: once the application has been discovered and blueprints have
+        #: been registered.
+        self.cli = cli.AppGroup()
+
+        # Set the name of the Click group in case someone wants to add
+        # the app's commands to another CLI tool.
+        self.cli.name = self.name
+
         # Add a static route using the provided static_url_path, static_host,
         # and static_folder if there is a configured static_folder.
         # Note we do this without checking if static_folder exists.