fix(templates): E2E Cookiecutter - Cover all REST authentication cases + one GraphQL case

[flexponsive]

Follow-up to #1410

• Expands the coverage of the end-to-test for cookiecutters to cover all authentication methods for REST
• Fixes misc issues discovered by mypy, including a missing import
• Add a test case for GraphQL

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📚 Documentation preview 📚: https://meltano-sdk--1428.org.readthedocs.build/en/1428/

[codecov]

Codecov Report

Merging #1428 (dd1a260) into main (14d7aa1) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main    #1428   +/-   ##
=======================================
  Coverage   85.47%   85.47%           
=======================================
  Files          57       57           
  Lines        4763     4763           
  Branches      808      808           
=======================================
  Hits         4071     4071           
  Misses        501      501           
  Partials      191      191           

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[tayloramurphy]

Thanks for the PR @flexponsive ! We'll get one of the engineers to review @meltano/engineering