Remove non actionable TODOs from Mp4Muxer code

PiperOrigin-RevId: 615372415

libraries/muxer/src/main/java/androidx/media3/muxer/FragmentedMp4Writer.java

@@ -179,8 +179,6 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
   private void createHeader() throws IOException {
     output.position(0L);
     output.write(Boxes.ftyp());
-    // TODO: b/262704382 - Add some free space in the moov box to fit any newly added metadata and
-    //  write moov box again in the close() method.
     // The minInputPtsUs is actually ignored as there are no pending samples to write.
     output.write(
         moovGenerator.moovMetadataHeader(

libraries/muxer/src/main/java/androidx/media3/muxer/Mp4Muxer.java

@@ -196,7 +196,6 @@ public final class Mp4Muxer {
   public static final ImmutableList<String> SUPPORTED_AUDIO_SAMPLE_MIME_TYPES =
       ImmutableList.of(MimeTypes.AUDIO_AAC);
 
-  // TODO: b/262704382 - Optimize the default duration.
   /**
    * The default fragment duration for the {@linkplain Builder#setFragmentedMp4Enabled(boolean)
    * fragmented MP4}.