Uncomfortable user experience because of mechanism with faucet codes (enhancement)

[rustam-RI]

Testing Environment:

Windows 10, Google Chrome 73.0.3683.86 (64bit), 15.6", 1920х1080

Steps to reproduce:

1. Navigate to https://faucet.singularitynet.io/
2. Log in to your GitHub account
3. Pay attention to the URL (it changed from https://faucet.singularitynet.io/ to https://faucet.singularitynet.io/index.html?code=********************, where *** is some code)
4. Request AGI for your wallet
5. Wait until you will see message about successful transaction
6. Request AGI for your wallet once again

EXPECTED RESULT:

I expect that user will be able to make a request once again or at least will see the message with info about when it will be possible to make the next request. If code is so important in this scheme then maybe the system can generate new code for the same GitHub account in case of the new request?

ACTUAL RESULT:

User sees an error message "Something went wrong! Reason: The code passed is incorrect or expired."