[Backport 2.x] feat: remove search index tool

[yuye-aws]

Description

Backport https://github.com/opensearch-project/skills/pull/295 to 2.x

Issues Resolved

Backport https://github.com/opensearch-project/skills/pull/295 to 2.x

Check List

• [ ] New functionality includes testing.
  • [ ] All tests pass
• [ ] New functionality has been documented.
  • [ ] New functionality has javadoc added
• [x] Commits are signed per the DCO using --signoff

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[yuye-aws]

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[yuye-aws]

Pushed a commit to fix the CI error.