fix(plugin): default value for tool execution response parameter type (#683)

Co-authored-by: mrh <mrh997>

backend/api/model/crossdomain/plugin/consts.go

@@ -77,6 +77,7 @@ type InvalidResponseProcessStrategy int8
 const (
 	InvalidResponseProcessStrategyOfReturnRaw     InvalidResponseProcessStrategy = 0 // If the value of a field is invalid, the raw response value of the field is returned.
 	InvalidResponseProcessStrategyOfReturnDefault InvalidResponseProcessStrategy = 1 // If the value of a field is invalid, the default value of the field is returned.
+	InvalidResponseProcessStrategyOfReturnErr     InvalidResponseProcessStrategy = 2 // If the value of a field is invalid, error is returned.
 )
 
 const (

backend/api/model/crossdomain/plugin/openai.go

@@ -181,6 +181,9 @@ func (op *Openapi3Operation) ToEinoSchemaParameterInfo(ctx context.Context) (map
 				if err != nil {
 					return nil, err
 				}
+				if subParam == nil {
+					continue
+				}
 
 				subParams[paramName] = subParam
 			}