unstructured

c04235c1 - fix [NEX-49] : Fix TypeError for empty HTML content (#4032)

fix [NEX-49] : Fix TypeError for empty HTML content (#4032) ### Summary Addressed a TypeError that occurred when partitioning empty or whitespace-only HTML content. ## Test * unit test `test_unstructured/partition/html/test_partition.py::test_partition_html_with_empty_content_raises_error` can reproduce the TypeErro before fix * now test can pass