fix dynamo converter test case failure

[lanluo-nvidia]

Description

example run:

https://github.com/pytorch/TensorRT/actions/runs/15669873129/job/44139691976?pr=3590
got
if converter_packet is None:

      raise UnsupportedOperatorException(

            f"Conversion of function {torch.typename(target)} not currently supported!"
        )

E torch_tensorrt.dynamo.conversion._TRTInterpreter.UnsupportedOperatorException: Conversion of function torch._ops.aten.aten::_assert_scalar not currently supported!

Fixes # (issue)
#3581

dynamo tracer with dynamic shape need to apply the post lowering passes to remove the _assert_scalar node

Type of change

Please delete options that are not relevant and/or add your own.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist:

• My code follows the style guidelines of this project (You can use the linters)
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas and hacks
• I have made corresponding changes to the documentation
• I have added tests to verify my fix or my feature
• New and existing unit tests pass locally with my changes
• I have added the relevant labels to my PR in so that relevant reviewers are notified

[narendasan]

LGTM