Repair wp/6.1 branch Actions: Replace wp-env's database check with a MariaDB health check - #84260

Part of #82932.

What?

Ports #75046 to this branch's wp-env: replaces the wp db check wait in wp-env start with a Docker health check on the MariaDB services, and makes WordPress wait for it (depends_on: condition: service_healthy).

Why?

The next PR in this stack, #84259, pins MariaDB 10.6. The MariaDB 11.8 client in the current wordpress:cli image requires TLS, which MariaDB before 11.4 doesn't offer, so without this change wp db check would fail with "SSL is required, but the server does not support it" and every job that starts wp-env would fail. Trunk removed wp db check in #75046; a health check doesn't use the MySQL client.

How?

• depends_on, start and clean follow wp-env: Fix MySQL startup race condition causing database connection errors #75046, adapted to this branch's file layout.
• The health check command is Env: Add an option to choose the MariaDB version #83751's: it runs healthcheck.sh only when the image and data volume support it, and otherwise pings MariaDB with mariadb-admin or mysqladmin, so older images (10.2/10.3, and tags without the script) still become healthy. Unlike wp/6.3 and newer, this branch's wp-env uses the stock wordpress:cli image without a generated Dockerfile, so Env: Add an option to choose the MariaDB version #83751's client wrappers can't be added; wp db commands still fail below 11.4, as the README notes.
• The tests from wp-env: Fix MySQL startup race condition causing database connection errors #75046 and Env: Add an option to choose the MariaDB version #83751 are ported, using .split().join() instead of replaceAll for Node 14. The changelog and README note are updated.

Verified locally: wp-env start works with MariaDB 10.6 and 10.3.

Use of AI Tools

This PR was created by Claude Code under my supervision. All code should be treated as AI-produced and not yet reviewed by a human until this PR is marked Ready for Review.