Sandbox: disable wiremock healthcheck

[czeni]

The port configuration (--port) of wiremock-based images (latest/3.12.1) is not propagated to its iherited
healtcheck command, thus it uses the default 8080 port in the test command's URL:

"Healthcheck": {
                "Test": [
                    "CMD-SHELL",
                    "curl -f http://localhost:8080/__admin/health || exit 1"
                ],
                "StartPeriod": 5000000000,
                "StartInterval": 100000000
            },

This means all wiremock-based containers eventually become unhealthy, which can cause trouble in sandbox-based tests cases.

Possible solution could be to set the command explicitly, but it seems unnecessary in a sandbox environment.