WalletConnection should return redirect links instead of redirect the whole page.

[DevSlashRichie]

Is your feature request related to a problem? Please describe.
I want to be able to use the link in an iframe or popup instead of redirecting the complete webapp.

Describe the solution you'd like
Allowing WalletConnection to have methods that return the redirect URI instead of ultimately returning the web page.

Describe alternatives you've considered
Embedding the whole near-api-js connect into its own code space and running that into a popup.

Additional context

near-api-js/packages/near-api-js/src/wallet-account.ts

Line 199 in 37ca222

window.location.assign(newUrl.toString());

[denbite]

the idea of having methods for generating a Wallet URL without redirecting looks also reasonable to me and was implemented in #1260