Previously, the algorithm that computes the String representation of a
class reference and a property type was shared. This lead to generic
information for group's `type` and `sourceType` property.

This commit separates that logic in two: `getQualifiedName` is now
responsible to generate a fully qualified class name while the existing
`getType` is solely responsible to generate a type representation for the
property. Only the latter has generic information.

Closes gh-7236