[hf] use fake api token in test configs

context:

• we were unwittingly depending on an env var (SIGNALBOOST_API_TOKEN) being defined in our gitlab settings to make route unit tests pass
• this is a brittle solution since it prevents unit tests from passing when people run them on their own test runners (plus we don't need the actual tokens for the test to work)

changes:

• this MR changes the api token to fakeToken in test env
• alongside that, we remove the following unnecessary env vars from our gitlab settings:
  • SIGNALBOOST_API_TOKEN
  • TWILIO_ACCOUNT_SID
  • TWILIO_AUTH_TOKEN