Base.createKeyPairHelper should use signerHost passed in the constructor.

[sboorlagadda]

createKeyPairHelper takes an argument signerHost and checks for length to be zero to decide which helper to return. Probably it should use what's passed to the constructor and make the argument completely optional, so if user wants to provide a different one he still an option.

const base = new Base("https://base-api.com", 'localhost', 'strategy', 'signerHost');
Base.createKeyPairHelper('signerHost') // Here argument should be optional