refactor(dev-env): migrate from @lando/phpmyadmin to phpmyadmin Docker image

[sjinks]

Description

The @lando/phpmyadmin plugin uses the old Docker image, phpmyadmin/phpmyadmin. That image is only built for the linux/amd64 architecture and does not work on AEM CPUs (Mac Mx chips).

We replace the plugin in this PR with the newer multiplatform phpmyadmin image.

Ref: 188043-z
Ref: https://hub.docker.com/r/phpmyadmin/phpmyadmin (the image used by Lando)
Ref: https://hub.docker.com/_/phpmyadmin (the multiplatform image)

Pull request checklist

• Update SETUP.md with any new environmental variables.
• Update the documentation.
• Manually test the relevant changes.
• Follow the pull request checklist
• Add/update automated tests as needed.

New release checklist

• Automated tests pass.
• The Preparing for release checklist is completed.

Steps to Test

Create a dev environment with phpMyAdmin enabled, start it, and ensure that it works and that Docker does not complain about the wrong architecture.

[github-actions]

Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

OpenSSF Scorecard

Package	Version	Score	Details

Scanned Manifest Files

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud