mariadb_repo_setup package doesn't work with MariaDB 10.6 and Debian 12 Bookworm

Because of the new mariadb-backup dump format, DDEV needs to install a matching mysql client in its webserver image instead of using the distribution default.

We would do this with the mariadb_repo_setup package, (see docs which call out doing this with 10.6)

ddev-webserver is based on Debian 12 Bookworm. mariadb_repo_setup doesn't work with Debian 12 Bookworm.

This is easy to demonstrate with `docker run -it --rm debian:bookworm bash -c 'apt update && apt install -y curl && curl -LsS https://r.mariadb.com/downloads/mariadb_repo_setup | bash -s – --mariadb-server-version="mariadb-10.6"'`

The output is
```

1. [info] Checking for script prerequisites.
2. [error] MariaDB Server version 10.6 is not working.
3. Please verify that the version is correct.
4. Not all releases of MariaDB are available on all distributions.
   #
5. The latest MariaDB Server versions are:
6. 10.4.34 10.5.25 10.6.18 10.11.8 11.0.6 11.1.5 11.2.4 11.4.2 11.5.1
   #
7. More information on MariaDB releases is available at:
8. https://mariadb.com/kb/en/release-notes/
   ```

Related issue where we're working on resolving this for DDEV is at https://github.com/ddev/ddev/issues/6083