Fix ClipQuantFusion crash when Clip has multiple input edges

[qti-yuduo]

Motivation

ClipQuantFusion in clip_quantizelinear.cc calls graph_utils::RemoveNode() without first checking graph_utils::CanRemoveNode(). When a Clip node has min/max inputs from DequantizeLinear nodes (instead of initializers), it has multiple input edges. RemoveNode() throws exception:

 [ONNXRuntimeError] : 6 : RUNTIME_EXCEPTION : Exception during initialization: graph_utils.cc:650 bool onnxruntime::graph_utils::RemoveNode(onnxruntime::Graph&, onnxruntime::Node&) Should be unreachable if CanRemoveNodeAndMergeEdges is in sync with the logic here.

Fix:

Added CanRemoveNode() check to ClipQuantFusion::SatisfyCondition() to skip nodes that cannot be safely removed.

Test:

Added ClipQuantFusion_MultipleInputEdges test that creates a Clip node with min from a DQ node (2 input edges) and verifies the optimizer doesn't crash.