fix: Only show proof of payment link when attachment exists

Added conditional check to display proof of payment link only when
utilBillsProofOfPaymentAttachment is present in LocationCard.

Previously the link was always rendered, even when no attachment
was uploaded. This fix ensures the link only appears when there's
actually a proof of payment file available.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

app/ui/LocationCard.tsx

@@ -70,7 +70,7 @@ export const LocationCard: FC<LocationCardProps> = ({ location, currency }) => {
                                 <CheckCircleIcon className="h-5 w-5 text-success" />
                             </div>
                         )}
-                        {(
+                        {utilBillsProofOfPaymentAttachment && (
                             <Link
                                 href={`/share/proof-of-payment/${_id}/`}
                                 target="_blank"