Revert removal of package required by mysqlclient

tests/integration/targets/setup_controller/tasks/requirements.yml

@@ -30,6 +30,12 @@
     name:
       - bzip2     # To test mysql_db dump compression
       - "{{ db_engine }}-client"
+
+      # The command mysql-config must be present for mysqlclient python package.
+      # The package libmysqlclient-dev that provides this command have a
+      # different name between Ubuntu 20.04 and 22.04. Luckily, libmysql++ is
+      # available on both.
+      - "{{ 'libmysql++-dev' if db_engine == 'mysql' else 'libmariadb-dev' }}"
     update_cache: true
     state: present