[cashtab-faucet] Let up a bit with the rate limiting

Summary: I run into the recaptcha bot error as a non bot almost all the time. So, the check is too strict. Likewise I am hitting the IP limiting for the free XEC claim and then it just never works. Want to prevent real users from this experience.

Test Plan: proofread, ack. We cannot really test this until we observe the new UX in prod. npm test to make sure we are not breaking anything.

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D18409