Goodbye, GraphQL (#24827)

```release-note
NONE
```

server/channels/web/handlers.go

@@ -408,14 +408,7 @@ func (h Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 
 		if r.URL.Path != model.APIURLSuffix+"/websocket" {
 			elapsed := float64(time.Since(now)) / float64(time.Second)
-			var endpoint string
-			if strings.HasPrefix(r.URL.Path, model.APIURLSuffixV5) {
-				// It's a graphQL query, so use the operation name.
-				endpoint = c.GraphQLOperationName
-			} else {
-				endpoint = h.HandlerName
-			}
-			c.App.Metrics().ObserveAPIEndpointDuration(endpoint, r.Method, statusCode, elapsed)
+			c.App.Metrics().ObserveAPIEndpointDuration(h.HandlerName, r.Method, statusCode, elapsed)
 		}
 	}
 }