Fix issue with older torch (openvinotoolkit#22592)

Author: mvafin

tools/ovc/openvino/tools/ovc/convert_impl.py

@@ -190,7 +190,7 @@ def check_model_object(argv):
             return "tf"
     if 'torch' in sys.modules:
         import torch
-        if isinstance(model, (torch.nn.Module, torch.jit.ScriptFunction, torch.export.ExportedProgram)):
+        if isinstance(model, (torch.nn.Module, torch.jit.ScriptFunction)) or (hasattr(torch, "export") and isinstance(model, (torch.export.ExportedProgram))):
             return "pytorch"
         try:
             from openvino.frontend.pytorch.ts_decoder import TorchScriptPythonDecoder

tools/ovc/openvino/tools/ovc/moc_frontend/pytorch_frontend_utils.py

@@ -34,7 +34,7 @@ def get_pytorch_decoder(model, example_inputs, args):
                 "NNCF models produced by nncf<2.6 are not supported directly. Please upgrade nncf or export to ONNX first.")
     inputs = prepare_torch_inputs(example_inputs)
     if not isinstance(model, (TorchScriptPythonDecoder, TorchFXPythonDecoder)):
-        if isinstance(model, torch.export.ExportedProgram):
+        if hasattr(torch, "export") and isinstance(model, (torch.export.ExportedProgram)):
             raise RuntimeError("Models received from torch.export are not yet supported by convert_model.")
         else:
             decoder = TorchScriptPythonDecoder(model, example_input=inputs, shared_memory=args.get("share_weights", True))