Normalize default chart range to lower case (alexjustesen#2443)

Co-authored-by: Alex Justesen <[email protected]>

Author: alexjustesen

config/speedtest.php

@@ -16,7 +16,7 @@
 
     'public_dashboard' => env('PUBLIC_DASHBOARD', false),
 
-    'default_chart_range' => env('DEFAULT_CHART_RANGE', '24h'),
+    'default_chart_range' => strtolower(env('DEFAULT_CHART_RANGE', '24h')),
 
     /**
      * Speedtest settings.