fix[__init__.py]: add password is empty check

radicale-auth-ldap/__init__.py

@@ -125,6 +125,11 @@ class Auth(BaseAuth):
         accessGroupFilter = self.configuration.get("auth", "ldap_access_group_filter")
         accessGroupAttribute = self.configuration.get("auth", "ldap_access_group_attribute")
 
+        if password == "":
+            logger.error("LDAP: user password is mandatory")
+
+            return ""
+
         if self.grantedUserAccessCache is not None:
             logger.info("LDAP: check if user is cached")