Remove usage of @ForOverride.

Fixes the gradle compilation failures.

Gradle dependencies need revising if we want to be using this, as
checkerframework is ahead of their latest version, such that we
can't compile.

PiperOrigin-RevId: 412004021

library/transformer/src/main/java/com/google/android/exoplayer2/transformer/TransformerBaseRenderer.java

@@ -29,7 +29,6 @@ import com.google.android.exoplayer2.decoder.DecoderInputBuffer;
 import com.google.android.exoplayer2.source.SampleStream.ReadDataResult;
 import com.google.android.exoplayer2.util.MediaClock;
 import com.google.android.exoplayer2.util.MimeTypes;
-import com.google.errorprone.annotations.ForOverride;
 import org.checkerframework.checker.nullness.qual.EnsuresNonNullIf;
 import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
 import org.checkerframework.checker.nullness.qual.RequiresNonNull;
@@ -134,7 +133,6 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
     isRendererStarted = false;
   }
 
-  @ForOverride
   @EnsuresNonNullIf(expression = "samplePipeline", result = true)
   protected abstract boolean ensureConfigured() throws ExoPlaybackException;