How to check the file format issues when we upload file using storage browser -AmplifyUI

Upload a non-CSV file and verify that the appropriate error message is displayed
I have tried using the getActionCompleteMessage: (files : File[]) => {
return { content : "Please upload a CSV file" , type : "warning"}},
But above warning message appears even when i user upload a CSV file , How can i check the fille format

Start with the Storage Browser upload flow and the getActionCompleteMessage callback shown in the issue, checking how the files: File[] value is passed for CSV and non-CSV uploads. Reproduce both cases and trace the callback result; done means the warning appears for non-CSV files without appearing for CSV files.

Written by the indexing model from the issue text.