Make userAuthenticationEmail optional for app-switch related flows

[saperi22]

Summary of changes

• Make userAuthenticationEmail optional for app-switch related flows

Checklist

• Added a changelog entry
• Relevant test coverage
• Tested and confirmed payment flows affected by this change are functioning as expected

Authors

List GitHub usernames for everyone who contributed to this pull request.

[sarahkoop]

Is this still a draft or ready for final review? Can we confirm the "Tested and confirmed payment flows affected by this change are functioning as expected" if ready for official review

[saperi22]

Is this still a draft or ready for final review? Can we confirm the "Tested and confirmed payment flows affected by this change are functioning as expected" if ready for official review

@sarahkoop
Apologies, I didn't see this message. I had to request app switch product team to enable the non-MPE flow. Testing is not complete yet.
As of today, I was able to verify the vault flow, but express checkout flow isn't enabled yet. I'm still waiting on that to be enabled before I can test it out. The code changes are done, but testing isn't complete, so I haven't opened this for review yet.

[saperi22]

Dev testing is complete.
@sarahkoop take another look if you want to. I'll merge it once you look at it.

[sarahkoop]

Dev testing is complete. @sarahkoop take another look if you want to. I'll merge it once you look at it.

LGTM! But we should wait to merge until we have E2E testing signoff and are ready to release

[jaxdesmarais]

➕ 1 on waiting until we get the okay from the E2E team. Ideally we can merge and release both iOS and Android at the same time.