only copy meta if available (#92623)
Test Plan:
```
buck2 test mode/opt //torchmultimodal/tests:tests -- --exact 'torchmultimodal/tests:tests - test_albef.py::test_albef_image_embeddings_momentum'
```
now passes
Reviewed By: malfet
Differential Revision: D42608385
Pull Request resolved: https://github.com/pytorch/pytorch/pull/92623
Approved by: https://github.com/tugsbayasgalan
