Never allow an empty password to validate (#9682) (#9683)

* Restore IsPasswordSet previous value

* Update models/user.go

Co-authored-by: Lauris BH <lauris@nix.lv>

models/user.go

@@ -503,7 +503,7 @@ func (u *User) ValidatePassword(passwd string) bool {
 
 // IsPasswordSet checks if the password is set or left empty
 func (u *User) IsPasswordSet() bool {
-	return len(u.Passwd) > 0
+	return !u.ValidatePassword("")
 }
 
 // UploadAvatar saves custom avatar for user.