Fix Plex login for users with 2FA enabled

[ericswpark]

This should fix login for Plex users using 2FA.

Closes #1584

TODO:

• Test that it works
• Test that commit doesn't break login for non-2FA users

[ericswpark]

Fixed a bug with the initial commit where the arguments were being passed to the wrong parameter^ (Blame me for being confused with Swiftlang and thinking Python did named parameter matching)

I've tested it and it works for both 2FA and non-2FA users!

[glensc]

So empty code is probably "", not None, that's fine too?

code = Prompt.ask(PROMPT_PLEX_CODE)
return MyPlexAccount(username=username, password=password, code=code)

[ericswpark]

@glensc I'm not sure what Prompt returns if the user leaves it empty, but I've confirmed that it works by creating a dummy account without 2FA. Either the plexapi library leaves it out intelligently, or the Plex API ignores the value if 2FA is not set up.

[simonc56]

Readme file should be updated too (remove line about code appended to password).

[ericswpark]

@twolaw done, just updated it :) Please let me know if there are other references that I may have missed.

[simonc56]

Remove comment import on line 17.