Properly quote the username to support usernames with spaces (#53420)

changelogs/fragments/ssh-quote-user.yaml

@@ -0,0 +1,2 @@
+bugfixes:
+- ssh - Properly quote the username to allow usernames containing spaces (https://github.com/ansible/ansible/issues/49968)

lib/ansible/plugins/connection/ssh.py

@@ -612,7 +612,7 @@ class Connection(ConnectionBase):
         if user:
             self._add_args(
                 b_command,
-                (b"-o", b"User=" + to_bytes(self._play_context.remote_user, errors='surrogate_or_strict')),
+                (b"-o", b'User="%s"' % to_bytes(self._play_context.remote_user, errors='surrogate_or_strict')),
                 u"ANSIBLE_REMOTE_USER/remote_user/ansible_user/user/-u set"
             )