Fixed: Document Loader Cannot Upload File with comma

[Hetsavani]

fixes: #4107

[HenryHengZJ]

thanks for the fix! we probably also need to handle the case for multiple file uploads

but files with comma name is not generally a common case, its better to rename the file without comma

[Hetsavani]

I have fixed issue happening on multiple file upload. Kindly check the last commit and tell me if there's any changes or feedback

[Hetsavani]

Can you please review my PR? @HenryHengZJ @jimjimovich @matthias