ci(test): replace the service principal with federated managed identity to access AKV

[JeyJeyGao]

CI:

• removed service principal.
• added federated credential with user assigned managed identity.
• added JS file in ./test/e2e/containerized/get_id_token to obtain the federated token for containerized testing.
• removed the check for branch source by using Github environment named E2E. The E2E test needs manually approved by the maintainers now.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 93.03%. Comparing base (501e0e6) to head (3d234e9).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #212   +/-   ##
=======================================
  Coverage   93.03%   93.03%           
=======================================
  Files          17       17           
  Lines         617      617           
  Branches       78       78           
=======================================
  Hits          574      574           
  Misses         31       31           
  Partials       12       12           

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