feat: add multi step registration eventing

[syedsajjadkazmii]

Description

This PR implements multi step registration experiment eventing

JIRA

VAN-1907

How Has This Been Tested?

Locally

Events:

Event	Props	Use
edx.bi.user.multistepregistration.step1.viewed	variation	is fired when user falls in a variation and lands on first step of registration
edx.bi.user.multistepregistration.step2.viewed	variation	is fired when user lands on second step of registration
edx.bi.user.multistepregistration.step3.viewed	none	is fired when user lands on second step of registration
edx.bi.user.registration.step1.submit.click	variation	is fired when user clicks CTA on first step of registration page
edx.bi.user.registration.step2.submit.click	variation	is fired when user clicks CTA on second step of registration page
edx.bi.user.registration.step3.submit.click	{}	is fired when user clicks CTA on third step of registration page
edx.bi.user.registration.form.submit.click	variation	is fired when user clicks CTA with valid data on first step in the CONTROL variant and on second step in multi step variant
edx.bi.user.registration.sso.btn.click	variation	is fired when user clicks SSO btn when lands on first step of registration page

Merge Checklist

• If your update includes visual changes, have they been reviewed by a designer? Send them a link to the Sandbox, if applicable.
• Is there adequate test coverage for your changes?

Post-merge Checklist

• Deploy the changes to prod after verifying on stage or ask @openedx/2u-vanguards to do it.
• 🎉 🙌 Celebrate! Thanks for your contribution.

[zainab-amir]

Why can't we add these conditions below?

[syedsajjadkazmii]

I may need more understanding of your comment. What does it mean by below?

By below do you mean along with step1 and step2 clicks? If yes, we can do that but we may need to change the code there as well. Those conditions are used for validating the steps of registration page except last step. So those conditions only run for non-last steps.

Adding here was simple and straight forward, therefore I added here.

But if meant something else, we can discuss.