PLT-2713 Added ability for admins to list users not in any team (#5844)

* PLT-2713 Added ability for admins to list users not in any team

* Updated style of unit test

store/store.go

@@ -177,6 +177,7 @@ type UserStore interface {
 	GetProfilesInChannel(channelId string, offset int, limit int) StoreChannel
 	GetAllProfilesInChannel(channelId string, allowFromCache bool) StoreChannel
 	GetProfilesNotInChannel(teamId string, channelId string, offset int, limit int) StoreChannel
+	GetProfilesWithoutTeam(offset int, limit int) StoreChannel
 	GetProfilesByUsernames(usernames []string, teamId string) StoreChannel
 	GetAllProfiles(offset int, limit int) StoreChannel
 	GetProfiles(teamId string, offset int, limit int) StoreChannel