Add missing audio Encoding value in Util method

AudioFormat.ENCODING_PCM_24BIT_PACKED was introduced in API 31
https://developer.android.com/reference/android/media/AudioFormat#ENCODING_PCM_24BIT_PACKED

PiperOrigin-RevId: 780996481
(cherry picked from commit 25bbb96)

Author: microkatz

libraries/common/src/main/java/androidx/media3/common/util/Util.java

@@ -2401,6 +2401,7 @@ public static int getApiLevelThatAudioFormatIntroducedAudioEncoding(int encoding
         return 28;
       case C.ENCODING_OPUS:
         return 30;
+      case C.ENCODING_PCM_24BIT:
       case C.ENCODING_PCM_32BIT:
         return 31;
       case C.ENCODING_DTS_UHD_P2: