Option to attach the last pvId automatically

[EPNW-Eric]

I think the documentation of attachLastPvId describes this PR pretty good:

  /// Whether to attach the last `pvId` to actions that can be associated with
  /// page views.
  ///
  /// There are some actions like [trackEvent] and [trackContentImpression]
  /// that can be associated with page views by setting a `pvId` (what is the
  /// abbreviation of page view id). If [attachLastPvId] is `true` and there is
  /// a last page view tracked by [trackScreenWithName] (or a method/class that
  /// uses it like [trackScreen], [TraceableClientMixin], [TraceableWidget]) the
  /// last recored `pvId` is automatically used unless it is overwritten in that
  /// action.
  late final bool attachLastPvId;