Replace `BitArray.skipBytes()` with `BitArray.skipBits()`

Based on the spec, ETSI TS 102 366 V1.4.1 Annex F, 6 bits should have skipped instead of 6 bytes.

This correction was pointed out in Issue: androidx/media#474.

PiperOrigin-RevId: 545658365
(cherry picked from commit 0f5b2cf9facbc8adac0d115896792de8db955da2)

library/extractor/src/main/java/com/google/android/exoplayer2/audio/Ac3Util.java

@@ -218,7 +218,7 @@ public final class Ac3Util {
     int numDepSub = dataBitArray.readBits(4); // num_dep_sub
     dataBitArray.skipBits(1); // numDepSub > 0 ? LFE2 : reserved
     if (numDepSub > 0) {
-      dataBitArray.skipBytes(6); // other channel configurations
+      dataBitArray.skipBits(6); // other channel configurations
       // Read Lrs/Rrs pair
       // TODO: Read other channel configuration
       if (dataBitArray.readBits(1) != 0) {