Fix subgraph quantization regression in onnxruntime 1.17 (#19421)
As per title, fixes
https://github.com/microsoft/onnxruntime/issues/19418
ONNX Runtime 1.17 broke the quantization of ONNX models with subgraphs
where initializers are placed on the top-level graph, while different
subgraphs use the same initializer.