[fix](regression) check partition minmax only

[shuke987]

Proposed changes

Backport #65180 to branch-4.1. On branch-4.1, partition_key_minmax still lives under nereids_p0/stats, so this applies the same final fix to the branch-specific path instead of directly picking the master file path.

The case is intended to validate partition-pruned partition-key min/max. The previous checks also depended on ndv/count, which can vary with async physical row-count reporting. This patch keeps the existing RANGE/LIST queries and checks only the partition-key min/max invariants.

Testing

• git diff --check -- regression-test/suites/nereids_p0/stats/partition_key_minmax.groovy
• git diff --check HEAD^ HEAD -- regression-test/suites/nereids_p0/stats/partition_key_minmax.groovy

Targeted regression was not run locally; CI will cover it.

[hello-stephen]

Thank you for your contribution to Apache Doris.
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Please clearly describe your PR:

1. What problem was fixed (it's best to include specific error reporting information). How it was fixed.
2. Which behaviors were modified. What was the previous behavior, what is it now, why was it modified, and what possible impacts might there be.
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4. Which code was refactored and why was this part of the code refactored?
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[shuke987]

run buildall

[shuke987]

/review

[github-actions]

Reviewed PR 65229. I did not find a blocking issue in this single-file regression-test backport.

The changed explain { check { ... } } assertions still fail when the expected partition-key min/max line is absent, because ExplainAction.check throws on a false Boolean result. The relaxed assertions match the stated intent: keep coverage for RANGE/LIST partition-key min/max while avoiding brittle ndv/count values that depend on async physical row-count reporting.

Validation performed:

• Read the review bundle context, existing review threads/comments, changed-file list, required AGENTS list, and shared ledger.
• Used GitHub PR metadata/patch as authoritative scope; local HEAD matches 44a76c2f97f2c9bc60ef968d693854daf30d6662.
• Reviewed regression-test/suites/nereids_p0/stats/partition_key_minmax.groovy, ExplainAction.check behavior, and the upstream PR 65180 backport shape.
• Ran git diff --check -- regression-test/suites/nereids_p0/stats/partition_key_minmax.groovy.

Limits: I did not run the targeted regression suite in this runner, and git diff --check HEAD^ HEAD could not be run because HEAD^ is unavailable in this grafted checkout.

User focus: no additional review focus was provided.

Subagent conclusions: the optimizer/rewrite subagent and the tests/session-config subagent both reported NO_NEW_VALUABLE_FINDINGS; no subagent candidate became an inline comment, and no duplicate candidate was merged. Final convergence round 1 ended with both live subagents reporting NO_NEW_VALUABLE_FINDINGS for this same no-inline-comment set.