Add MRC continuous play API to IMA android sdk.

Details in
go/ima-mrc-continuous-play

Corresponding js webcore changes is in <unknown commit>.

NoExternal

PiperOrigin-RevId: 253585186

extensions/ima/src/test/java/com/google/android/exoplayer2/ext/ima/FakeAdsRequest.java

@@ -106,6 +106,11 @@ public final class FakeAdsRequest implements AdsRequest {
   }
 
   @Override
+  public void setContinuousPlayback(boolean b) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
   public void setContentDuration(float v) {
     throw new UnsupportedOperationException();
   }