Remove unused import in IpSecAlgorithm

HexDump is an internal class which cannot be visible to mainline
module. Remove it since this is unused.

Bug: 204153604
Test: FrameworksNetTests
Change-Id: Ie65e7eff8464487719c3124005a097a500ba21c6

framework-t/src/android/net/IpSecAlgorithm.java

@@ -23,7 +23,6 @@ import android.os.Parcel;
 import android.os.Parcelable;
 
 import com.android.internal.annotations.VisibleForTesting;
-import com.android.internal.util.HexDump;
 
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;