refactor max users per team (#7691)

store/store.go

@@ -88,7 +88,7 @@ type TeamStore interface {
 	GetByInviteId(inviteId string) StoreChannel
 	PermanentDelete(teamId string) StoreChannel
 	AnalyticsTeamCount() StoreChannel
-	SaveMember(member *model.TeamMember) StoreChannel
+	SaveMember(member *model.TeamMember, maxUsersPerTeam int) StoreChannel
 	UpdateMember(member *model.TeamMember) StoreChannel
 	GetMember(teamId string, userId string) StoreChannel
 	GetMembers(teamId string, offset int, limit int) StoreChannel