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

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

* s/Api/API/g

model/command.go

@@ -99,7 +99,7 @@ func (o *Command) IsValid() *AppError {
 		return NewAppError("Command.IsValid", "model.command.is_valid.url.app_error", nil, "", http.StatusBadRequest)
 	}
 
-	if !IsValidHTTPUrl(o.URL) {
+	if !IsValidHTTPURL(o.URL) {
 		return NewAppError("Command.IsValid", "model.command.is_valid.url_http.app_error", nil, "", http.StatusBadRequest)
 	}