create_signed_url doesn't use Bearer token from sign_in

[Jonathan Fischoff]

Describe the bug
create_signed_url fails when authorization is necessary because the wrong Bearer token is being used in the request

To Reproduce
Steps to reproduce the behavior:

1. Create a storage policy that requires a particular user to view it
2. Use sign_in_with_password to sign in as that user
3. Use create_signed_url to try to create a presigned url
4. Get a 400 instead.

Expected behavior
200 and the signed url

I debugged this by running mitmproxy. The request showed the initial anon bearer token.

When I saved the failed request as a curl and replaced the bearer token with the one returned from sign_in_with_password it worked.

[Anand]

Fixed by supabase/supabase-py#560