Use replaceState instead of a redirect to strip the loginToken
Put user into the same post-auth flows of E2ESetup
Skip UIA prompt in this post-auth flow, happy path is a server grace period
With this change, Element now creates cross-signing keys during auth flows for
password login. For other auth flows like token / SSO, it will not happen until
a cross-signing / secret storage dialog flow as before.
Instead of twisting `AuthBody`, this adds a new component for the different
styling of post-auth security flows. This also makes them fixed width and
adjusts padding to match designs.
