[High5] Improve PIN setup screen browser test

Refactor the screen's browser test to simplify the addition of future
test cases that will be added for the High5 project.

- Add utility function for configuring PIN policies.
- Add method to simplify metrics expectations and remove boilerplate.
- Make the default fixture simulate login support.
- Standardize the web interaction via simple methods.

Also, add a couple of test cases to ensure that the screen is skipped
when extra_factors_token is missing, or when the token is expired.

Bug: b/365059362, b/348326316
Change-Id: Ia493463fc8146601e83e4dedc6435f7e6acde327
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5872824
Reviewed-by: Simon Hangl <simonha@google.com>
Commit-Queue: Renato Silva <rrsilva@google.com>
Reviewed-by: Hardik Goyal <hardikgoyal@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1357112}