[dy] Add try/except

[dy46]

Description

Try .fillna('') for every column and catch the exception if it fails. This should resolve the most critical issue for now.

How Has This Been Tested?

• Tested locally with bug reproduction steps in the issue.

Checklist

• The PR is tagged with proper labels (bug, enhancement, feature, documentation)
• I have performed a self-review of my own code
• I have added unit tests that prove my fix is effective or that my feature works
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• If new documentation has been added, relative paths have been added to the appropriate section of docs/mint.json

cc: @wangxiaoyou1993