Updates sample cert and admin keystore

[DarshitChanpura]

Description

Downstream change coming from security plugin: https://github.com/opensearch-project/security/pull/4061

Check List

• [ ] New functionality includes testing.
  • [ ] All tests pass, including unit test, integration test and doctest
• [ ] New functionality has been documented.
  • [ ] New functionality has javadoc added
  • [ ] New functionality has user manual doc added
• [x] Commits are signed per the DCO using --signoff

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[DarshitChanpura]

should be merged post https://github.com/opensearch-project/security/pull/4061 is merged

[DarshitChanpura]

can you leave some comments as to why this change is needed?

Downstream change coming from security plugin: https://github.com/opensearch-project/security/pull/4061 CI will start failing because of certificate mismatch, since the public certificates used are updated, thus sample.pem will not be verifiable since it has old certs

Can you provide a mechanism to pull these in via security plugin?

This is left onto maintainers to refactor build.gradle to pull artifacts from security repository. Refer to k-NN's build.gradle.

These certificates should not be hardcoded in individual plugin repos instead they should be pulled from security-plugin as needed. Even better solution would be to generate own certificates and setup the configuration as required, thus avoiding any dependency on security plugin's certificates.

[gaiksaya]

Hello reviewers,

This could be potential reason for failing tests with security atleast at the distribution level for 2.13.0. Please review and merge. Looks like it would need backport to 2.x and 2.13?

Thanks!