Translate access token instead of id token to gRPC backend in Flyte Admin HTTP middleware

[Sovietaced]

Tracking issue

Closes #5978

Why are the changes needed?

See #5978

What changes were proposed in this pull request?

HTTP middleware translates session cookies into gRPC metadata containing the access token as opposed to the id token

Note: This has a subtle side effect that with blanket authorization the access token must include the all scope.

How was this patch tested?

Unit tests

Setup process

Screenshots

Check all the applicable boxes

• I updated the documentation accordingly.
• All new and existing tests passed.
• All commits are signed-off.

Related PRs

Docs link

[codecov]

Codecov Report

Attention: Patch coverage is 64.28571% with 5 lines in your changes missing coverage. Please review.

Project coverage is 36.90%. Comparing base (25cfe16) to head (d46690b).

Files with missing lines	Patch %	Lines
flyteadmin/auth/handlers.go	64.28%	4 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5979      +/-   ##
==========================================
+ Coverage   33.09%   36.90%   +3.80%     
==========================================
  Files        1013     1310     +297     
  Lines      107489   131381   +23892     
==========================================
+ Hits        35570    48480   +12910     
- Misses      68767    78687    +9920     
- Partials     3152     4214    +1062     

Flag	Coverage Δ
unittests-datacatalog	51.58% <ø> (ø)
unittests-flyteadmin	54.05% <64.28%> (?)
unittests-flytecopilot	22.23% <ø> (ø)
unittests-flytectl	62.39% <ø> (-0.05%)	⬇️
unittests-flyteidl	6.92% <ø> (ø)
unittests-flyteplugins	53.84% <ø> (ø)
unittests-flytepropeller	42.90% <ø> (ø)
unittests-flytestdlib	55.31% <ø> (ø)

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