[5.2] check for getUrl method on the adapter before throwing exceptio…

…n - Filesystem (#14246)

* check for getUrl method on the adapter

It is better to check if the $adapter supports a getUrl function instead of telling that this driver does not support retrieving URLs.

* fix the typo

* styling fix

FilesystemAdapter.php

@@ -238,6 +238,8 @@ public function url($path)
             return $adapter->getClient()->getObjectUrl($adapter->getBucket(), $path);
         } elseif ($adapter instanceof LocalAdapter) {
             return '/storage/'.$path;
+        } elseif (method_exists($adapter, 'getUrl')) {
+            return $adapter->getUrl($path);
         } else {
             throw new RuntimeException('This driver does not support retrieving URLs.');
         }