feat(apollo): Use HTTP headers instead of query parameters for authorization

[mattcreaser]

• PR title and description conform to Pull Request guidelines.

Issue #, if available:

Description of changes:
AppSync recently added the ability to use HTTP headers instead of query parameters to authorize the websocket connection request. This is now the recommended way to connect (and new AppSync instances will eventually stop accepting query parameters).

This change switches the apollo-appsync library to use this new method of authorization.

How did you test these changes?

• Added unit tests
• Manual test passes
• Integration tests still pass

Documentation update required?

• No
• Yes (Please include a PR link for the documentation update)

General Checklist

• Added Unit Tests
• Added Integration Tests
• Security oriented best practices and standards are followed (e.g. using input sanitization, principle of least privilege, etc)

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 44.01%. Comparing base (7f874ed) to head (bfb3cf9).
Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2916      +/-   ##
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- Coverage   44.01%   44.01%   -0.01%     
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  Files         926      931       +5     
  Lines       30485    30688     +203     
  Branches     4351     4496     +145     
==========================================
+ Hits        13419    13507      +88     
- Misses      15601    15697      +96     
- Partials     1465     1484      +19