[BugFix] dnn (ONNX): Foce dropping constant inputs in parseClip if they are shared opencv#25319
Resolves opencv#25278
Merge with opencv/opencv_extra#1165
In Gold-YOLO ,`Div` has a constant input `B=6` which is then parsed into a `Const` layer in the ONNX importer, but `Clip` also has the shared constant input `max=6` which is already a `Const` layer and then connected to `Elementwise` layer. This should not happen because in the `forward()` of `Elementwise` layer, the legacy code goes through and apply activation to each input. More details on opencv#25278 (comment).
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