Issue #3412255: Warning: Undefined array key media in...

Issue #3412255: Warning: Undefined array key media in CssOptimizer->processFile() after update from 1.19.0 to 1.20.0

Closes #3412255

src/Asset/CriticalCssProvider.php

@@ -184,6 +184,7 @@ class CriticalCssProvider implements CriticalCssProviderInterface {
             'type' => 'file',
             'preprocess' => TRUE,
             'data' => $filePath,
+            'media' => 'all',
           ]) :
           trim(file_get_contents($filePath));
         break;