fix(sdk-extension-aws): replace deprecated aws-auth ConfigMap check with JWT iss claim detection in AwsEksResourceDetector (#4414)

* fix(sdk-extension-aws): fix AwsEksResourceDetector on EKS Access Entries API clusters

Replace aws-auth ConfigMap HTTP check with JWT iss claim decode. Clusters
using the Access Entries API do not have aws-auth, causing HTTP 404 and
silent empty resource. Pod service-account token iss always contains
oidc.eks on EKS. Decoded locally, no network call required.

* Add unit tests for JWT-based EKS detection in AwsEksResourceDetector

* use regex-based JWT issuer validation instead of string matching

* test(aws-sdk-extension): add non-EKS JWT raise path test

* Apply suggestion from @MikeGoldsmith

* style(aws-sdk-extension): minor formatting cleanup in EKS detector

* add changelog 4414 file

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Co-authored-by: Mike Goldsmith <goldsmith.mike@gmail.com>
Co-authored-by: Emídio Neto <9735060+emdneto@users.noreply.github.com>
Co-authored-by: Aaron Abbott <aaronabbott@google.com>