[native] [13/34] ReactNav6: add setParams to NavigationHelpers

Summary:
See context in D5402. We omitted this initially since it would cause type errors. Now that we've fixed up all of the usages, we can introduce it without type errors.

Depends on D5405

Test Plan: Flow + ran the app on my phone and played around with it

Reviewers: atul, tomek, bartek

Reviewed By: atul

Subscribers: abosh

Differential Revision: https://phab.comm.dev/D5406