Files upload with same name

[sadiq1971]

Describe the bug
File upload with same name(in same directory) doesn't return conflict error

To Reproduce
Steps to reproduce the behavior:

1. Go to the app
2. Upload a file named xyz
3. Upload another file named xyz with different content
4. Doesn't return error and the file is not replaced either.

Expected behavior
Backend returns conflict error for the files.
Files upload is a batch operation and if there is conflict error for some files the upload returns all the entries for files and there status whether it got uploaded successfully or failed. UI needs to check the response.
The best way will be

1. Call check-upload API before uploading and inform user about the conflicting files to re- add files while uploading.
2. Check the response of the upload and inform about the failed files while uploading