[MM-37772] Idiomatic naming (URL, URI, API) (#18128)

* s/Url/URL/g & s/Uri/URI/g

* s/Api/API/g

api4/cluster.go

@@ -10,7 +10,7 @@ import (
 )
 
 func (api *API) InitCluster() {
-	api.BaseRoutes.Cluster.Handle("/status", api.ApiSessionRequired(getClusterStatus)).Methods("GET")
+	api.BaseRoutes.Cluster.Handle("/status", api.APISessionRequired(getClusterStatus)).Methods("GET")
 }
 
 func getClusterStatus(c *Context, w http.ResponseWriter, r *http.Request) {