Fix docker stuff for new mariadb:lts

[anomiex]

Proposed changes:

It seems that MariaDB released a new lts, which dropped a bunch of the compatibility mysql-named symlinks from their docker image. This broke a bunch of our stuff.

• Change the health command passed to Docker.
• Use new names in the dev env db upgrade wrapper script.
• Pass the correct command to the dev env DB container.

Also I noticed our tests workflow was still using MySQL 5.6, while WordPress now requires either MySQL 8.0+ or MariaDB 10.4+. Updated to the latter there too.

Other information:

• Have you written new tests for your changes, if applicable?
• Have you checked the E2E test CI results, and verified that your changes do not break them?
• Have you tested your changes on WordPress.com, if applicable (if so, you'll see a generated comment below with a script to run)?

Jetpack product discussion

p1717161929313609/1717160529.942769-slack-C034JEXD1RD

Does this pull request change what data or activity we track or use?

No

Testing instructions:

• Do a docker pull mariadb:lts, then make sure that jetpack docker down and jetpack docker up still work.
• CI happy? Especially Tests and E2E Tests.
  • https://github.com/Automattic/jetpack/actions/runs/9319590833/job/25654503380?pr=37659#step:2:80
  • https://github.com/Automattic/jetpack/actions/runs/9319590815/job/25654738059#step:9:418
• We'll probably have to merge this to test whether it makes the Post-Build workflow happy.

[github-actions]

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[tbradsha]

Why --su-mysql?

[anomiex]

Copied from the first example at https://mariadb.com/kb/en/using-healthcheck-sh/#examples, since it seemed to work.