Check users logged in to moose earlier in workflow

Users are encountering the moo login errors quite often e.g.

```
Selecting variables to process from stream onm.
Checking the status of previously stored data and comparing to the data requested to be stored in this operation.
User Error while running MASS command: "moo ls -Rl /CMIP7/CMIP/UKNCSP/UKESM1-3-LL/esm-hist/r1i1p1f1".
This could cause by a wrong mooseURI, a wrong password or insufficient permissions on a data set.
MOO command standard error "ls, command-id=a316502a-0c64-4be0-a738-ed0a2baed385, (NOT_LOGGED_IN) run 'moo login' to continue.
ls: failed (2)
```

```
cdds.common.mass_exception.MassError: User Error while running MASS command: "moo ls -RlESM1-3-LL/esm-hist/r1i1p1f1".
This could cause by a wrong mooseURI, a wrong password or insufficient permissions on a data set.
```

Would be good to have some sort of check for this early (and instruct users to do a moo login if it fails) when cdds_convert is run to prevent workflows being stopped unnecessarily (At start of any extract or transfer command?).