Fix gosec lint issues

[dmathieu]

This fixes the new lint issues so #6101 can upgrade golangci-lint.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.

Project coverage is 65.7%. Comparing base (774b20e) to head (c381e51).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...lang.org/grpc/otelgrpc/internal/test/test_utils.go	0.0%	2 Missing ⚠️

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #6107   +/-   ##
=====================================
  Coverage   65.7%   65.7%           
=====================================
  Files        203     203           
  Lines      13039   13039           
=====================================
  Hits        8570    8570           
  Misses      4206    4206           
  Partials     263     263           

Files with missing lines	Coverage Δ
...lang.org/grpc/otelgrpc/internal/test/test_utils.go	50.0% <0.0%> (ø)