fix: TRTInterpreter output lacks return value

- Fixes error causing PyTree failures during Dynamo tracing for new
converters returning lists of Tensors

Author: gs-olive

py/torch_tensorrt/dynamo/conversion/trt_interpreter.py

@@ -356,3 +356,5 @@ def output(self, target, args, kwargs):
             elif self.output_fp16 and output.dtype == trt.float32:
                 output.dtype = trt.float16
             self._output_names.append(name)
+
+        return list(outputs)