Use "services" in GitHub actions

[fbacall]

Summary of changes

• Replace custom actions that run Postgres & Redis with GitHub's own containerized services.

Motivation and context

Action run failed due to rate limit hit: https://github.com/ElixirTeSS/TeSS/actions/runs/20440274417/job/58731372004#step:5:18

docker: Error response from daemon: toomanyrequests: You have reached your unauthenticated pull rate limit. https://www.docker.com/increase-rate-limit.

and possibly GitHub does some caching/mirroring when you use its built-in services that could avoid this...?

Checklist

• I have read and followed the CONTRIBUTING guide.
• I confirm that I have the authority necessary to make this contribution on behalf of its copyright owner and agree
  to license it to the TeSS codebase under the
  BSD license.

[Copilot]

Pull request overview

This PR modernizes the GitHub Actions workflow configuration by replacing third-party container actions with GitHub's native containerized services for PostgreSQL and Redis. The motivation is to avoid Docker Hub rate limiting issues that caused recent CI failures.

• Migrated PostgreSQL from harmon758/postgresql-action@v1 to native GitHub services
• Migrated Redis from supercharge/redis-github-action@1.5.0 to native GitHub services
• Standardized Redis port from 6456 to 6379 in the test workflow

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
.github/workflows/test.yml	Replaced custom Postgres and Redis actions with native GitHub services; updated Redis port from 6456 to 6379; added health checks for both services
.github/workflows/deployment-checks.yml	Replaced custom Postgres action with native GitHub services; added Redis service with health checks

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