preloaded-classes-denylist: remove retired class

Remove com.android.server.BootReceiver$2 from the denylist as this
anonymous class was retired in change https://r.android.com/1565971.

Bug: 159164105
Bug: 179645293
Test: atest PreloadCheck
Change-Id: I94122241dc4cef84524ca83513a68d1fa8ffbe65

config/preloaded-classes-denylist

@@ -4,7 +4,6 @@ android.os.FileObserver
 android.os.NullVibrator
 android.speech.tts.TextToSpeech$Connection$SetupConnectionAsyncTask
 android.widget.Magnifier
-com.android.server.BootReceiver$2
 gov.nist.core.net.DefaultNetworkLayer
 android.net.rtp.AudioGroup
 android.net.rtp.AudioStream