Add Cancel Button and Conditional Next Button when we Upload Pdf

## Current Behavior
- Next button is always visible even when no content is present
- Users need to refresh the page to clear uploaded file content
- No way to cancel or clear file selection without page refresh

## Proposed Changes
- Add a Cancel button next to Browse File button to clear content
- Make Next button conditional - only show when content is present
- Add clear functionality to remove file content without page refresh