fixed the fileUpload component and also added the test cases

[armaang1729]

Fix: File Upload Re-upload Issue

Description

This PR fixes a critical bug in the FileUpload component where users could not re-upload the same file after removing it. Another was to support the file upload feature in which the user can upload multiple files with same name.

Key Changes:

• Clear file input value after file selection to enable re-uploading the same file
• Implement unique identifier (UID) system for better file tracking and duplicate handling
• Added tests for re-upload scenarios and duplicate filename handling

Related Issue

• FileUpload component bug #156

Motivation and Context

How Has This Been Tested?

• Unit Tests Added:

  • should allow re-uploading same file after removal - Tests the core bug fix
  • should handle duplicate filenames correctly without removing wrong file - Tests improved file tracking with UIDs

• Manual Testing:

  1. Upload a file → verify it appears in the list
  2. Remove the file → verify it's removed from the list
  3. Upload the same file again → verify it can be re-uploaded successfully
  4. Test with multiple files having the same name → verify correct file is removed

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• I have signed the Adobe Open Source CLA.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[rismehta]

LGTM. Thanks