Install mariadb-client for mysqldump command

When using the nova to placement db migration script, debian users will have
issues using the mysqldump command as the mariadb-client-core package doesn't
include this command. The packages installed for the other distros do install
mysqldump alongside more tooling, this would bring debian to feature parity.

db migration script:
https://opendev.org/openstack/placement/raw/branch/master/placement_db_tools/mysql-migrate-db.sh

What we currently have:
https://packages.ubuntu.com/disco/amd64/mariadb-client-core-10.3/filelist
What we could have:
https://packages.ubuntu.com/disco/amd64/mariadb-client-10.3/filelist
Example of what an other distro gets:
see line 543, # mariadb-client.files
https://build.opensuse.org/package/view_file/server:database/mariadb/mariadb.spec

Depends-On: https://review.opendev.org/#/c/695238/
Change-Id: I50b1cde1a82a855d54c54b43f8d141df9583205c

vars/debian.yml

@@ -18,7 +18,7 @@ _galera_client_repo_url: "http://{{ galera_repo_host }}/MariaDB/mariadb-{{ galer
 _galera_client_repo: "deb {{ galera_client_repo_url }} {{ ansible_distribution_release }} main"
 
 galera_client_distro_packages:
-  - "mariadb-client-core-{{ galera_client_major_version }}"
+  - "mariadb-client-{{ galera_client_major_version }}"
 
 # Galera GPG Keys
 _galera_client_gpg_keys: