[native] replace keyserver using qr code auth

Summary:
if a user attempts to add a second keyserver via qr code auth, we should prompt them to either replace their existing keyserver or cancel the auth attempt.

Depends on D12809

Test Plan:
created new authoritative keyserver with username jackson, user ID D753543A-F5C9-4058-B6D8-DF9398C5AB51, device ID 25k0GJ+aTm1NQGZOo+5MkhRUBqhWfi66s2I3tIB38cQ

registered new user jacks with user ID 528DBB32-D52C-4B1F-8604-06F36B8AAFBB, device ID /fAt0mtfRH8mlRL9gjFVZmSfwTG7kSQ0hZ9kwuKxaiQ

spun up docker keyserver on port 3001

added keyserver as secondary device

removed mariadb volume and spun up another docker keyserver

REPLACED first keyserver with second in device list successfully

successfully added a web secondary device to ensure that i didn't break the existing workflow

Reviewers: bartek, tomek, ashoat

Reviewed By: bartek, tomek, ashoat

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D12884