This is a spin-off of T7502 which was created before team keys materialized in Kleopatra.
In general, when importing a secret team key the question whether the importing user is the only user of the key is pretty useless because the purpose of team keys is to be shared among several users. Team keys that are created with Kleopatra are tagged with a group flag. Hence it's possible to detect team keys when a key is imported.
When a secret team key (i.e. a public key with the group flag and secret subkeys) is imported then Kleopatra should not ask the user whether they are the only user of the key. This avoids confusing the user with a useless question. Instead the users will immediately asked whether they want to certify the key.