ASM - Use finishing instead of isState() and more logging

The following changes are added for go/activity-security:

1. Use `finishing` rather than `isState(FINISHING)` for detecting
   finishing activities. isState does not always return true if an
   activity finishes and the one below it immediately starts another.
2. Update toasts to be more succinct as they are limited to two lines.
   Change their duration to be longer so they are easier to read.
3. Log ASM activity if toasts are enabled, regardless of enforcement.
4. Log more information about the task environment.

Test: atest ActivitySecurityModelTest ActivitySecurityModelEmbeddingTest
BackgroundActivityLaunchTest
Bug: 269253404, 248045984

Change-Id: Ifd72b9b9762a654e5581c3861115420c4a02a4c6