fix tool selector with empty tools raise error (#15829)

api/core/plugin/entities/parameters.py

@@ -147,7 +147,7 @@ def init_frontend_parameter(rule: PluginParameter, type: enum.StrEnum, value: An
     init frontend parameter by rule
     """
     parameter_value = value
-    if not parameter_value and parameter_value != 0:
+    if not parameter_value and parameter_value != 0 and type != PluginParameterType.TOOLS_SELECTOR:
         # get default value
         parameter_value = rule.default
         if not parameter_value and rule.required: