fix: test with run image

[SalimKayal]

• feat: Add multi-arch support, update run-image, and streamline build process #97
  • Fix: Refactor Image Naming and Versioning #110
    • this
      • fix: Update RStudio version and OS_CODENAME #108

This PR updates the test.yaml workflow to build and push a custom run-image to GHCR before running tests. This custom image is then used for the tests.

Key changes:

• Build and Push run-image: A new step is added to build a run-image from the ./run-image directory.
• Update builder.toml: Before running tests, the builder.toml file is modified to use the newly built run-image tag.

This change ensures that the tests are always run with the latest run-image built from the repository, providing better consistency and allowing for easier testing of run-image changes.

closes #105