fix: handle lead/lag extreme offset overflow cases (#22221, #22231)

[Dandandan]

Motivation

• Prevent panics and overflow when lead/lag are used with extreme offsets such as i64::MIN and i64::MAX by handling those edge cases explicitly.
• Ensure lead/lag evaluation returns the configured default value or a descriptive error instead of crashing during planning or execution.

Description

• Change WindowShiftKind::shift_offset to return Result<i64> and use checked_neg for lead to detect and reject i64::MIN with a DataFusionError::Execution error.
• Update partition_evaluator to propagate the new Result from shift_offset and keep the reversal logic intact when needed.
• Replace unchecked index arithmetic in WindowShiftEvaluator::evaluate with checked_sub and safe usize conversion so extreme offsets do not overflow and out-of-range indices map to the default value.
• Remove an unused import and add two regression unit tests: test_lead_i64_min_offset_returns_error and test_lead_i64_max_offset_evaluate_returns_default to cover both issue cases.

Testing

• Ran cargo fmt --all which completed successfully.
• Ran cargo clippy --all-targets --all-features -- -D warnings, which reported a pre-existing unrelated compilation error in datafusion/physical-plan/benches/aggregate_vectorized.rs and therefore did not fully complete in this environment.
• Added unit tests under datafusion/functions-window for the regressions; full test execution in CI is recommended to validate across the repository's build matrix.

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Codex Task