Validate CUDA GatherElements count (#32030)
This pull request adds a validation step to the CUDA `GatherElements`
kernel to ensure the number of output elements does not exceed the
supported limit, preventing potential overflows or runtime errors. It
also introduces a corresponding utility function and unit tests for this
validation.
**CUDA GatherElements Kernel Improvements:**
* Added a call to `ValidateGatherElementsElementCount` in
`gather_elements.cc` to check that the number of output elements does
not exceed `INT32_MAX`, ensuring CUDA kernel compatibility and
preventing overflows.
* Implemented the inline function `ValidateGatherElementsElementCount`
in `gather_elements.h` to encapsulate the element count validation
logic.
* Included `<limits>` in `gather_elements.h` to support numeric boundary
checks.
**Testing:**
* Added unit tests in `gather_elements_op_test.cc` to verify that
`ValidateGatherElementsElementCount` correctly accepts valid counts and
rejects counts exceeding `INT32_MAX`.
