Fix race conditions in the Authentication client

[rdeaton-freenome]

Related: #2626

Why are the changes needed?

The AuthorizationClient may need to pop up a webbrowser for human interaction to auth, and may do so from multiple threads and multiple grpcio channels. This manifested for us in race conditions during pyflyte register because it uses concurrent registration

flytekit/flytekit/tools/repo.py

Lines 310 to 311 in 1cc2b11

	cp_task_entities = list(filter(lambda x: isinstance(x, task.TaskSpec), registrable_entities))
	asyncio.run(_register(cp_task_entities))

What changes were proposed in this pull request?

We block all threads and allow a single request through for authorization and cache that result for a short window to make sure that we don't need a separate request per-thread, and avoid the race condition on setting up the local HTTP server for handling the redirect.

How was this patch tested?

Lots of calls to pyflyte register in a repository with a large number of workflows.

Check all the applicable boxes

• I updated the documentation accordingly. (docstrings, at least)
• All new and existing tests passed.
• All commits are signed-off.

[thomasjpfan]

Otherwise LGTM

[codecov]

Codecov Report

Attention: Patch coverage is 25.00000% with 15 lines in your changes missing coverage. Please review.

Project coverage is 78.78%. Comparing base (286b17f) to head (aaa5828).
Report is 42 commits behind head on master.

Files	Patch %	Lines
flytekit/clients/auth/auth_client.py	25.00%	15 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2635      +/-   ##
==========================================
+ Coverage   76.04%   78.78%   +2.73%     
==========================================
  Files         186      187       +1     
  Lines       19081    19190     +109     
  Branches     3765     4008     +243     
==========================================
+ Hits        14510    15118     +608     
+ Misses       3914     3378     -536     
- Partials      657      694      +37     

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