Add metrics to track impact of blocking weak passwords

We want to track how often the weak_password validation is blocking weak passwords. This will enable us to measure impact, and correlate against other metrics such as a potential decrease in sign up rates.

Proposal

From #363445 (comment 1110733738)

I'd recommend we fire the structured event below when the weak password warning message is displayed. More details on snowplow implementation can be found here and here. If you have any specific questions about implementing the event, feel free to ping us in the g_acquisition slack channel, as our team has implemented a lot of these events.

category	action	Label	Additional context to capture	Notes (reference for this issue, not an actual snowplow event property)
default from page fired on	activate_form_input	warning_weak_password	page_url snowplow_session_id	Event fires when we render the warning that the users password is too weak