DIA-2065 / DIA-2120 fix state management for authenticated consent and handle pv-data response

[andresilveirah]

This PR addresses 2 items:

State management when authId changes

The SDK now correctly implements the following logic, related to state management when authId changes:

1. authId changes from nil -> "something": state is persisted (consent is then linked to the current uuid)
2. authId changes from "something" -> nil: state is persisted (stored authId remains "something")
3. authId changes from "something" -> "something else": state is reset (and authId becomes "something else")

Handling /pv-data response

The /pv-data endpoint not only logs a "pageview" but also returns a new consent uuid for a given campaign.

Previously the SDK would not wait for the response of /pv-data. And this causes issues with reporting as well as a missing consent uuid in the stored consent data (until the user takes a consent action).