Log interaction for when user leaves interstitial without using the UI

As part of expanding anti-phishing telemetry, we want to know if users
are deciding not to proceed through means other than the interstitial UI
("Back to Safety" button). This will help us understand how effective
our UI is at warning users about phishing sites. We also added logging
for user action sequences for interactions with the phishing
interstitial.

Bug: 1439670
Change-Id: I2f37ef615d4b143bef8752298da8cfadcbc3cc58
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4469476
Code-Coverage: Findit <findit-for-me@appspot.gserviceaccount.com>
Reviewed-by: Daniel Rubery <drubery@chromium.org>
Commit-Queue: Sarah Krakowiak <skrakowi@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1136174}