fix: added new parse rule for correctly parsing ports without protocol specifier

[lexain12]

Also edited corresponding test.
It would be great if you could merge it into the 24 release.

Problem

After update of docker from 27.5.1 to 28.3.0, build 38b7060 error related to port parsing occured. Specifically port parsing fails on port without protocol specifier.
Maybe this issue will help clarify things.
Here is docker inspect on running scylladb/scylla:6.0 docker container, created with testcontainers api using different version of docker.

docker inspect (27.5.1 version)

"Ports": {
                "10000/tcp": [
                    {
                        "HostIp": "0.0.0.0",
                        "HostPort": "55062"
                    }
                ],
                "22/tcp": [
                    {
                        "HostIp": "0.0.0.0",
                        "HostPort": "55056"
                    }
                ]
}

docker inspect (28.3.0 version)

            "Ports": {
                "10000": [],
                "10000/tcp": [
                    {
                        "HostIp": "0.0.0.0",
                        "HostPort": "55475"
                    }
                ],
                "22": [],
                "22/tcp": [
                    {
                        "HostIp": "0.0.0.0",
                        "HostPort": "55469"
                    }
                ]
}

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[DDtKey]

As far as I understand, with this fix we will be able to parse this successfully, but only the last definition will be preserved—since Ports is effectively represented as two separate hash maps.

I'm not entirely sure what the correct behavior should be here. For example, if docker/moby reorders the entries in a future version, we could end up losing the actual HostPort value 🤔

[lexain12]

In my opinion, this is fundamentally wrong behavior in Docker and should be fixed, because there must not be two definitions for a single port. So, I'm aiming to resolve this issue to prevent the application from crashing.