`oauth-role-mapping.properties` incorrectly expects a external role to be prefixed with 'ROLE_'

### Current Behavior
`IbisAdmin=ExternalIdpRole` doesn't work anymore, you need to specify `IbisAdmin=ROLE_ExternalIdpRole` to make the mapping work as expected.

### Expected Behavior
The role mapping works like it did before the change for #9872.

### Environment Information
9.4 and 10.0-SNAPSHOT

### Anything else?
You can obviously work around this issue by prefixing your role with 'ROLE_'