Fix filename for accelerated uploads

What does this MR do?

Sets upload's filename from the original name if accelerated uploads are used. It also sanitizes filename.

Are there points in the code the reviewer needs to double check?

FileUploader's filename now takes into account also @filename || super, is there a place where this could cause a problem?

Why was this MR needed?

When accelerated upload is used for file uploads, the file's name is set from the temporary filename instead of using original name.

The problem is that FileUploader overrides filename and doesn't take into account @filename variable which keeps the original filename.

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• Conform to the code review guidelines
  • Has been reviewed by a UX Designer
  • Has been reviewed by a Frontend maintainer
  • Has been reviewed by a Backend maintainer
  • Has been reviewed by a Database specialist
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conform to the database guides
• If you have multiple commits, please combine them into a few logically organized commits by squashing them
• Internationalization required/considered
• End-to-end tests pass (package-and-qa manual pipeline job)

What are the relevant issue numbers?

#49297 (closed)