gdpr_consent is ignored in test mode

[davidc]

This line in session.py:

        # Record GDPR consent status
        self.gdpr_consent = gdpr_consent or test

ignores the developer's explicit rejection of consent to transmit personal data when in test mode. I don't believe this is okay, there is no reason to be overriding their decision and silently sending the data anyway - not to mention that this data is even more personally-identifying and sensitive when running in test mode as it is likely to be on their personal computer.