Fix slurmrestd version function

[rstyd]

This PR fixes the slurmrestd inference function. It also adds a debug message that states what version it finds.

[pagrubel]

@rstyd Should there be a fix for the configuration file?

[pagrubel]

Please remove api version from config and use whatever is installed.

[pagrubel]

I tried this out with and without slurmrestd and it seems to work well. I haven't reviewed the changes yet.

[kchilleri]

This also works for me + I can find the openapi_version in the beeflow logs.