Replace Hard-coded HTTP Verbs with Constants (#27219)

* Replace hard-coded HTTP verbs with constants in `net/http`

server/channels/api4/license_local.go

@@ -15,8 +15,8 @@ import (
 )
 
 func (api *API) InitLicenseLocal() {
-	api.BaseRoutes.APIRoot.Handle("/license", api.APILocal(localAddLicense, handlerParamFileAPI)).Methods("POST")
-	api.BaseRoutes.APIRoot.Handle("/license", api.APILocal(localRemoveLicense)).Methods("DELETE")
+	api.BaseRoutes.APIRoot.Handle("/license", api.APILocal(localAddLicense, handlerParamFileAPI)).Methods(http.MethodPost)
+	api.BaseRoutes.APIRoot.Handle("/license", api.APILocal(localRemoveLicense)).Methods(http.MethodDelete)
 }
 
 func localAddLicense(c *Context, w http.ResponseWriter, r *http.Request) {