web: remove no longer needed mime type definition

It's built-in now.

web/rootfs/defaults/nginx.conf

@@ -32,8 +32,6 @@ http {
 
  	include /etc/nginx/mime.types;
 	types {
-		# add support for wasm MIME type, that is required by specification and it is not part of default mime.types file
-		application/wasm wasm;
 		# add support for the wav MIME type that is requried to playback wav files in Firefox.
 		audio/wav        wav;
 	}