Fixing no rendering of Play-Only-Mode (sugarlabs#4494)

Signed-off-by: Justin Charles <charlesjustin2124@gmail.com>

Author: justin212407

index.html

@@ -11,6 +11,7 @@
     <meta name="description"
         content="Learn to code through music with Music Blocks. Arrange colorful blocks to create everything from simple melodies to interactive games.">
     <meta name="mobile-web-app-capable" content="yes">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <meta name="theme-color" content="#2196F3">
     <title>Music Blocks</title>