docker.GetContainers(true, $"<filter>"); with filter that returns no results results in all results being returned as results

[devedse]

For some reason it seems that when I provide a filter to docker.GetContainers which has no matching results ends up with all containers being returned.
When I check the Xunit logs it runs 2 commands which is strange:

Ductus.FluentDocker: cmd: C:\Program Files\Docker\Docker\resources\bin\docker.exe - arg:  -H npipe:https:////./pipe/docker_engine ps  --all --filter expose=5123 --quiet --no-trunc
Ductus.FluentDocker: cmd: C:\Program Files\Docker\Docker\resources\bin\docker.exe - arg:  -H npipe:https:////./pipe/docker_engine ps --all --quiet --no-trunc
Ductus.FluentDocker: cmd: C:\Program Files\Docker\Docker\resources\bin\docker.exe - arg:  -H npipe:https:////./pipe/docker_engine inspect 437775a2c7292c82a82ead90cf3088bf1094cfddd4a4f241291b48179b280b87 613af9b1dbb635db....
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[mariotoffia]

Thanks for your PR!! I'll merge it today!! :)