Add Amplitude event for visiting the self-paced PL marketing page

[TurnerRiley]

Adds a new Amplitude event for visiting a marketing page (the self-paced PL marketing page in this case). This event was added following the same format as other marketing page visit events.

Amplitude logging event (locally)

Links

Jira ticket: here
Associated Amplitude event: here
Reference PR: here

Testing story

Localhost testing.

PR Checklist:

• Tests provide adequate coverage
• Privacy and Security impacts have been assessed
• Code is well-commented
• New features are translatable or updates will not break translations
• Relevant documentation has been added or updated
• User impact is well-understood and desirable
• Pull Request is labeled appropriately
• Follow-up work items (including potential tech debt) are tracked and linked

[davidsbailey]

Unfortunately I don't think this is going to work very well, because this page is cached:

That means that many requests for this page are served by cloudfront, without hitting our servers.

I am also just realizing that we may have the same problem on other pegasus pages where we try to record amplitude events.

I could be missing something here, but I think we are going to have to have a conversation with the product team about what we need this metric for, since it is not clear to me that amplitude (as we are currently using it) is going to be effective.

[davidsbailey]

TurnerRiley do you think you could gather a list of which amplitude metrics we're trying to capture upon viewing of a pegasus page, so we can try and figure out which metrics we may need to investigate? metrics which are captured in response to a user action on the page can be excluded since those should be working properly.

[davidsbailey]

Apologies @TurnerRiley , per https://codedotorg.slack.com/archives/C0453TUMLE7/p1684443407266619?thread_ts=1684442534.547659&cid=C0453TUMLE7 I realized this should be working fine, because we do the logging from js, which will be executed regardless of whether the page is cached. this change LGTM!