Fix allowlist token issues

1) Don't accept enqueued notifications with an unexpected token.
2) Ensure allowlist token matches for all parceled and unparceled notifications (by only using the "root notification" one).
3) Simplify cookie usage in allowlist token serialization.
4) Ensure group summary (and any notifications added directly by NMS) have the correct token.

Bug: 328254922
Bug: 305695605
Test: atest NotificationManagerServiceTest ParcelTest CloseSystemDialogsTest + manually
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:8a7453435b633282a9445ee01a902f090adc138c)
Merged-In: I232e9b74eece745560ed2e762071b48984b3f176
Change-Id: I232e9b74eece745560ed2e762071b48984b3f176