LibAudio: Sleep less when the audio buffer is full

When using `aplay` to play audio files with a sample rate of 96000,
there were occasional one-second gaps in playback. This is
because the Audio::ClientConnection sleeps for a full second when
the audio buffer is full.

One second is too long to sleep, especially for high-bitrate files.
Changing the sleep to a more reasonable value like 100 ms ensures
we attempt to enqueue again before the audio buffer runs empty.

Userland/Libraries/LibAudio/ClientConnection.cpp

@@ -20,7 +20,7 @@ void ClientConnection::enqueue(const Buffer& buffer)
         auto success = enqueue_buffer(buffer.anonymous_buffer(), buffer.id(), buffer.sample_count());
         if (success)
             break;
-        sleep(1);
+        sleep(.1);
     }
 }