Fix missing grouping after shade closes

Log BaseHeadsUpEntry map

Make logs more readable

Fixes: 367403822
Fixes: 356516285

Test: HeadsUpManagerPhoneTest

Test: send message HUN from two contacts from same app
      open shade, close shade
      => see that HUNs are grouped

Test: send delayed HUN, open shade, close shade before delayed HUN
      times out
      => see no disappear animation (no regression)

Test: adb shell cmd statusbar echo -b NotifHeadsUpLog:verbose
      adb reboot
      adb logcat | grep HeadsUpManager

Flag: com.android.systemui.notification_avalanche_throttle_hun
Change-Id: I88a8f76e63a82fa0473f18b2d5384bcf39209f27