[Autofill Framework] Update some confusing save related debug logs

1. AutofillManagerServiceImpl#finishSessionLocked: While it's printing whether save is shown, it's logging a value that's rather confusing. For example "finishSessionLocked(): session finished on save? true" actually means session finished, save UI did not show.

2. AutofillManager#notifyViewVisibilityChangedLocked. Both save trigger id and dialog tracking id are using the exact same log "No more visible ids. Invisible = ", it's hard to differentiate which kind of views are becoming invisible.

3. Session#updateTrackedIdsLocked. Not sure why there is a "=>" between "trackedViews" and "fillableIds". A develper reading the log may think the framework is trying to update the "trackedViews" to be "fillableIds", which is not the case.

Bug: b/334165576
Test: atest CtsAutoFillServiceTestCases
Change-Id: I61e169b5a25dcc9b7b40a7a18c87644a83a2096b