#ExoPlayerMigration Ensure RawResourceDataSource class is obfuscated

PiperOrigin-RevId: 355659628

library/core/proguard-rules.txt

 # Proguard rules specific to the core module.
 
 # Constant folding for resource integers may mean that a resource passed to this method appears to be unused. Keep the method to prevent this from happening.
--keep class com.google.android.exoplayer2.upstream.RawResourceDataSource {
+-keepclassmembers class com.google.android.exoplayer2.upstream.RawResourceDataSource {
   public static android.net.Uri buildRawResourceUri(int);
 }