fix: Use correct service key for security proxy auth

[jinlinGuan]

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[cloudxxx8]

LGTM

[codecov-commenter]

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Codecov Report

Attention: Patch coverage is 0% with 4 lines in your changes missing coverage. Please review.

Project coverage is 28.07%. Comparing base (6bbd37b) to head (dc34042).

Files with missing lines	Patch %	Lines
internal/security/proxyauth/main.go	0.00%	4 Missing ⚠️

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Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5020   +/-   ##
=======================================
  Coverage   28.07%   28.07%           
=======================================
  Files         243      243           
  Lines       17590    17590           
=======================================
  Hits         4938     4938           
  Misses      11524    11524           
  Partials     1128     1128           

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