Add % instead of the default 'localhost' since we use remote connection

Previously, everything was on localhost. Now ansible-test is in a
venv and the db is in a container. The db see the IP address from the
podman host (10.88.0.2)

tests/integration/targets/test_mysql_user/tasks/test_user_password.yml

@@ -24,6 +24,7 @@
       mysql_user:
         <<: *mysql_params
         name: '{{ test_user_name }}'
+        host: '%'
         password: '{{ initial_password }}'
         priv: '{{ test_default_priv }}'
         state: present