fix a bug were lc3 streams wouldnt stop

src/auracast/multicast.py

@@ -447,8 +447,13 @@ class Streamer():
                     lc3_frame = bytes(
                         itertools.islice(big['lc3_frames'], big['lc3_bytes_per_frame'])
                         )
+
+                    if lc3_frame == b'': # Not all streams may stop at the same time
+                        stream_finished[i] = True
+                        continue
                 else:
                     pcm_frame = await anext(big['audio_input'].frames(big['lc3_frame_samples']), None)
+
                     if pcm_frame is None: # Not all streams may stop at the same time
                         stream_finished[i] = True
                         continue