Fix rotary embedding oob issue (#29014)
This pull request improves the validation logic for the RotaryEmbedding
operator to prevent out-of-bounds reads when the rotary embedding
dimension derived from `cos_cache` exceeds the input tensor's
`hidden_size`. It also adds dedicated unit tests to verify that this
validation triggers as expected.
**Validation improvements:**
* Added a check in `rotary_embedding_helper.h` to ensure that the
effective rotary embedding dimension (`cos_cache` width × 2) does not
exceed `hidden_size` when `rotary_embedding_dim` is 0, returning an
error if the condition is violated.
**Unit test additions:**
* Added `ContribRotaryEmbedding_RejectsCosCacheExceedsHiddenSize` test
in `rotary_embedding_op_test.cc` to verify that an invalid configuration
is correctly rejected in the contrib op.
* Added `RotaryEmbedding_RejectsCosCacheExceedsHiddenSize` test in
`rotary_embedding_op_test.cc` (providers/cpu/llm) to verify the same
validation in the mainline op.
