Fix test reference file (#3443)

Author: FloatingCrowbar

ydb/core/http_proxy/ut/internal_counters.json

@@ -372,6 +372,30 @@
       "value": 50,
       "kind": "RATE"
     },
+    {
+      "kind":"RATE",
+      "labels":  {
+        "cloud_id":"cloud4",
+        "database":"/Root",
+        "database_id":"database4",
+        "folder_id":"folder4",
+        "name":"topic.write.discarded_bytes",
+        "topic":"test-counters-stream"
+      },
+      "value":0
+    },
+    {
+      "kind":"RATE",
+      "labels": {
+        "cloud_id":"cloud4",
+        "database":"/Root",
+        "database_id":"database4",
+        "folder_id":"folder4",
+        "name":"topic.write.discarded_messages",
+        "topic":"test-counters-stream"
+      },
+      "value":0
+    },
     {
       "labels": {
         "name": "topic.write.message_size_bytes",