aiograpi: Unsafe signup challenge path handling

aiograpi is an asynchronous Instagram API for Python. aiograpi versions before 0.9.10 accepted server-supplied signup challenge paths and used them to build request URLs before validating that the paths were relative Instagram API paths. If an attacker can influence a challenge response, for example through a local network, DNS, or proxy compromise, challenge handling requests could be sent outside the intended Instagram host with the client's existing session headers. Version 0.9.10 validates challenge paths before building URLs, solving captcha challenges, or submitting phone/SMS challenge forms.