fix bug: input q/k/v should not be modified by operator (microsoft#20555

)

### Description
<!-- Describe your changes. -->
Operator should not modify input tensors because they are managed by
framework and may be reused by other nodes.


### Motivation and Context
<!-- - Why is this change required? What problem does it solve?
- If it fixes an open issue, please link to the issue here. -->

onnxruntime/contrib_ops/cpu/bert/group_query_attention.cc

@@ -103,17 +103,13 @@ Status GroupQueryAttention<T>::Compute(OpKernelContext* context) const {
   if (packed_qkv) {
     ORT_RETURN_IF_ERROR(MaybeTransposeToBNSH<T>(
         allocator, batch_size, num_heads_ + 2 * kv_num_heads_, sequence_length, head_size, query, Q));
-  } else if (sequence_length > 1) {
+  } else {
     ORT_RETURN_IF_ERROR(MaybeTransposeToBNSH<T>(
         allocator, batch_size, num_heads_, sequence_length, head_size, query, Q));
     ORT_RETURN_IF_ERROR(MaybeTransposeToBNSH<T>(
         allocator, batch_size, kv_num_heads_, sequence_length, head_size, key, K));
     ORT_RETURN_IF_ERROR(MaybeTransposeToBNSH<T>(
         allocator, batch_size, kv_num_heads_, sequence_length, head_size, value, V));
-  } else {
-    Tensor::InitOrtValue(std::move(const_cast<Tensor&>(*query)), Q);
-    Tensor::InitOrtValue(std::move(const_cast<Tensor&>(*key)), K);
-    Tensor::InitOrtValue(std::move(const_cast<Tensor&>(*value)), V);
   }
 
   if (do_rotary_) {