Merge pull request #18096 from l-bat:update_onnx_importer

* Added ReduceSum to ONNX importer

* Fix comments

* Fix Mul

modules/dnn/src/layers/fully_connected_layer.cpp

@@ -116,7 +116,6 @@ public:
             CV_CheckEQ(inputs.size(), (size_t)2, "");
             numOutput = inputs[1].back();
             cAxis = inputs[0].size() - 1;
-            CV_CheckEQ(numOutput, inputs[0][cAxis - 1], "");
             int dims = inputs[0].size();
             CV_CheckEQ(inputs[1].size(), (size_t)dims, "");
             CV_CheckGE(dims, 2, "");