[keyserver] Ensure that we're including calendarQuery in siweAccountCreationRequest

Summary: This is needed for successful registration when we call the siwe_auth endpoint from web. I should have included this earlier.

Test Plan: Able to step through account creation and ensure that every step completes as expected.

Reviewers: ashoat, tomek

Reviewed By: ashoat

Differential Revision: https://phab.comm.dev/D6339