Refactor File Download Logic and Streamline Test Suite (#9281)

Closes #9277 

## Summary of Changes
- Updated the file-download functionality to use the `saveAs` method
from the `file-saver` library, ensuring a more reliable and consistent
implementation.
- Removed redundant tests to streamline the test suite and reduce
maintenance overhead.

## Testing Performed
- [x] Verified that exporting the view to a CSV file works as expected.

packages/twenty-front/src/modules/activities/files/utils/downloadFile.ts

@@ -1,3 +1,4 @@
+import { saveAs } from 'file-saver';
 import { getFileAbsoluteURI } from '~/utils/file/getFileAbsoluteURI';
 
 export const downloadFile = (fullPath: string, fileName: string) => {
@@ -8,13 +9,6 @@ export const downloadFile = (fullPath: string, fileName: string) => {
         : Promise.reject('Failed downloading file'),
     )
     .then((blob) => {
-      const url = window.URL.createObjectURL(blob);
-      const a = document.createElement('a');
-      a.style.display = 'none';
-      a.href = url;
-      a.download = fileName;
-      document.body.appendChild(a);
-      a.click();
-      window.URL.revokeObjectURL(url);
+      saveAs(blob, fileName);
     });
 };