Fix TreeEnsemble target id validation (#29293)
## Fix TreeEnsemble target id validation
### Problem
`TreeEnsemble` opset 5 normalizes `leaf_targetids` into the internal
v3-shaped attributes without going through the v3 attribute constructor.
Invalid target ids could therefore reach the N-output aggregators, where
Min/Max indexed the `predictions` vector without a bounds check.
### Fix
- Centralize target/class id validation in `TreeEnsembleCommon::Init()`
so all normalized entry paths are covered.
- Reject non-positive target/class counts, negative target/class ids,
and ids greater than or equal to the target/class count.
- Add defense-in-depth target index checks in Sum/Min/Max N-output
aggregators before indexing `predictions`.
- Add v5 negative tests and update affected v3 regressor negative test
expectations.
### Testing
- `lintrunner` on changed files
- rebuilt `onnxruntime_provider_test`
- targeted provider tests:
- `MLOpTest.TreeEnsembleFloat`
- `MLOpTest.TreeEnsembleDouble`
- `MLOpTest.TreeEnsembleSetMembership`
- `MLOpTest.TreeEnsembleLeafOnly`
- `MLOpTest.TreeEnsembleMinLeafTargetIdsOutsideBoundary`
- `MLOpTest.TreeEnsembleMaxLeafTargetIdsOutsideBoundary`
- `MLOpTest.TreeEnsembleNegativeLeafTargetIds`
- `MLOpTest.TreeEnsembleZeroTargets`
- `MLOpTest.TreeEnsembleLeafLike`
- `MLOpTest.TreeEnsembleBigSet`
- `MLOpTest.TreeEnsembleIssue25400`
- `MLOpTest.TreeRegressorNegativeTargetIds`
- `MLOpTest.TreeRegressorOutsideBoundaryTargetIds`
- `MLOpTest.TreeEnsembleRegressorTargetIdsOutsideBoundary`
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Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
