Remove testing harness

[justinbarry]

Replace bundled dev wallet with https://github.com/onflow/fcl-next-harness.

[gregsantos]

Should wait until FCLCrypto contract is deployed on emulator by default or may lead to issues attempting to verify account-proof on authn

[chasefleming]

@justinbarry @gregsantos Heads up it looks like this may break the cypress tests. Looks like it uses harness as its baseUrl.

[justinbarry]

My thinking was that we could import the other harness as a dependency and host it here.

[gregsantos]

That would work, but if there's a test for login/authn will fail unless FCLCrypto contract is deployed to emulator