RFE: Option to explicitely state that MMS is not supported

According to the community support of my provider (simpel.nl), my provider does not support MMS any more at all.

In my Librem 5 logging, I see this warning:

Bearer Handler emitted an error, the mmsc is not configured right.
Could not find settings: Operator ID '20416' not found in service provider database
Your MMS settings are not in the database! Please file a merge request at ...

My request is to be able to explicitly state that a provider does not support MMS, to prevent this warning in the journal, and also to inform software that it is expected that MMS is not working with this provider.

See also issue #11 (where it is also stated there that that provider explicitly does not support MMS).