HTTP prefix require sometimes in HyP3 URL

[jhkennedy]

I recently noticed that I can connect and auth to a HyP3 deployment even if I don't provide https:// as part of the API URL:

>>> import hyp3_sdk as sdk
>>> hyp3 = sdk.HyP3('hyp3-api.asf.alaska.edu')

but if I try and interact with HyP3 at all, I get a requests exception:

>>> hyp3.my_info()
Traceback (most recent call last):
  File "/home/jhkennedy/mambaforge/envs/RAiDER/lib/python3.12/site-packages/IPython/core/interactiveshell.py", line 3548, in run_code
    exec(code_obj, self.user_global_ns, self.user_ns)
  File "<ipython-input-4-4c1162596b76>", line 1, in <module>
    hyp3.my_info()
  File "/home/jhkennedy/mambaforge/envs/RAiDER/lib/python3.12/site-packages/hyp3_sdk/hyp3.py", line 487, in my_info
    response = self.session.get(urljoin(self.url, '/user'))
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/jhkennedy/mambaforge/envs/RAiDER/lib/python3.12/site-packages/requests/sessions.py", line 602, in get
    return self.request("GET", url, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/jhkennedy/mambaforge/envs/RAiDER/lib/python3.12/site-packages/requests/sessions.py", line 575, in request
    prep = self.prepare_request(req)
           ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/jhkennedy/mambaforge/envs/RAiDER/lib/python3.12/site-packages/requests/sessions.py", line 486, in prepare_request
    p.prepare(
  File "/home/jhkennedy/mambaforge/envs/RAiDER/lib/python3.12/site-packages/requests/models.py", line 368, in prepare
    self.prepare_url(url, params)
  File "/home/jhkennedy/mambaforge/envs/RAiDER/lib/python3.12/site-packages/requests/models.py", line 439, in prepare_url
    raise MissingSchema(
requests.exceptions.MissingSchema: Invalid URL '/user': No scheme supplied. Perhaps you meant https:///user?

I think we should handle this better either by adding the https:// ourselves or rejecting URLs that don't have it when we instantiate the HyP3 class.