fix: 修复错误率error_rate计算错误 (#3002)

# Reviewed, transaction id: 18581

bkmonitor/packages/apm_web/topo/handle/relation/endpoint_top.py

@@ -121,8 +121,8 @@ def get_mapping(cls, metric):
             total_mapping.setdefault(span, 0)
             total_mapping[span] += value
 
+            error_mapping.setdefault(span, 0)
             if status_code == str(StatusCode.ERROR.value):
-                error_mapping.setdefault(span, 0)
                 error_mapping[span] += value
 
             endpoint_names.add(span)
@@ -132,7 +132,6 @@ def get_mapping(cls, metric):
     def convert_mapping_to_list(self, total_mapping, error_mapping, endpoint_names):
         res = []
         for index, name in enumerate(endpoint_names, 1):
-
             error_rate = round(error_mapping[name] / total_mapping[name], 2) if total_mapping[name] else 0
             if error_rate == 0:
                 color = NodeColor.Color.GREEN
@@ -240,7 +239,6 @@ class ApdexList(EndpointList):
     metric = ApdexInstance
 
     def list(self):
-
         response = self.metric(
             **self.common_params, **{"filter_dict": self.get_filter_dict(), "group_by": ["span_name"]}
         ).get_instance_calculate_values_mapping(