Cannot enable SSO on Ceph Dashboard (missing python3-saml)

# Issue report

## What version of MicroCeph are you using ?
reef/stable

## What are the steps to reproduce this issue ?

Attempt to enable SSO on dashboard:
```
$ ceph dashboard sso setup saml2 http://10.10.0.40:8080 http://10.10.2.34:8080/realms/master/protocol/saml/descriptor
Error EPERM: Required library not found: `python3-saml`
```
## What happens (observed behaviour) ?

ERROR:
```
Error EPERM: Required library not found: `python3-saml`
```

## What were you expecting to happen ?

The command returns the json output of the SSO configuration.