[DEDUPE-TEST][BUG] Unified query API fails with date types in PPL

[qianheng-aws]

Describe the bug

When using the unified query API (_plugins/_query) with PPL queries involving date types, the query fails with an unexpected error. This appears to be related to date type handling in the PPL execution path.

To reproduce

1. Create an index with a date field
2. Run a PPL query via _plugins/_query that filters on the date field
3. Observe the error

Expected behavior

The query should return results correctly when filtering on date fields.

OpenSearch version

3.6.0

[github-actions]

Possible Duplicate

Found 1 possible duplicate issue(s):

• [BUG] Unified query API fails with date types #5250 — [BUG] Unified query API fails with date types

If this is not a duplicate:

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Otherwise, this issue will be automatically closed in ${DUPLICATE_GRACE_DAYS:-7} days.

🤖 Generated with Claude Code

[ahkcs]

Can you add more details to the description?
Also, please follow the PPL bug report template:
https://github.com/opensearch-project/sql/blob/main/.github/ISSUE_TEMPLATE/ppl_bug_report.md

[qianheng-aws]

This is a test issue for dedupe workflow, it will be auto closed in 7 days. We can ignore it.