Unable to provide command-line arguments to runner service containers

Describe the enhancement
I would like to be able to provide command-line arguments to a service container.

Code Snippet
docker-compose currently handles this with the command directive:

version: "3"
services:
  keycloak:
    image: quay.io/keycloak/keycloak:19.0.2
    command: start-dev --features=preview
    environment:
    - KEYCLOAK_ADMIN=keycloak
    - KEYCLOAK_ADMIN_PASSWORD=password
    - KC_LOG_LEVEL=INFO
    - KC_DB=dev-mem
    ports:
    - 8080:8080

The API for actions could look like this:

jobs:
  test:
    services:
      keycloak:
        image: quay.io/keycloak/keycloak:19.0.2
        ports:
          - 8080:8080
        env:
          KC_DB: dev-mem
          KC_LOG_LEVEL: INFO
          KEYCLOAK_ADMIN: keycloak
          KEYCLOAK_ADMIN_PASSWORD: password
        command: start-dev --features=preview

Additional information
If you're working with a docker image that only specifies a script as the ENTRYPOINT, then there is no feasible way to use this image as a service container within GitHub Actions if you need to specify additional arguments. Here's a list of everything I tried:

• I tried using options to set the --entrypoint flag when starting the container, but that doesn't work when trying to set arguments for the entrypoint script.
• I tried putting a script into my repository that would run the command with the arguments I want, that I could then mount to the service container as a volume. This doesn't work because the volume mount would happen before my repository code is cloned down within the workflow.

Right now, the only possible workaround is for me to build and push my own container that uses my desired container as a base, and overrides the ENTRYPOINT to specify the arguments I want. This is not a good long-term solution, as my test suite runs on three different versions of this software, so I need to maintain three different containers that have this fix.

No files, tests, or entry points are named. Start by tracing how the runner creates Docker service containers and passes existing options to the container invocation. Done means a workflow service can declare command-line arguments like the proposed command field and the behavior is covered by runner tests.