[native] Introduce placeholder CommunityCreationMembers component

Summary:
Just the plumbing for navigation, will actually be implemented in subsequent diffs.

Depends on D7980

Test Plan:

1. Successfully create community via CommunityConfiguration
2. Ensure that CommunityCreationMembers is navigated to as expected

Looks as expected:

Reviewers: ashoat, ginsu

Reviewed By: ashoat

Subscribers: tomek

Differential Revision: https://phab.comm.dev/D7987