Create a function to distinguish between an untrusted and a trusted credential
In order to level up their lox credential, a client has to make a specific request to the distributor to check that their bridges have not been blocked and retrieve the updated credential. The endpoint used varies depending on if a user is trust level 0 (untrusted), or trust levels >= 1 (trusted).
To ease the process of deciding which endpoint to contact, it would be useful to have a function somewhat similar to invitation_is_trusted
but for the credentials themselves.