fix: correct property name for file UUID in FileElementController

The FileElementService::getVisibleElementFromProperties() method expects
the 'uuid' key but the controller was passing 'fileUuid', causing the
file lookup to fail with 'File not found for visible element' error.

This fixes the issue where creating file elements (visible signature
elements) via the API endpoint /api/v1/file-element/{uuid} was failing
with a 404 error.

Fixes: Behat test 'Request to sign using email as identifier and when
is necessary to use visible elements'

Author: vitormattos

lib/Controller/FileElementController.php

@@ -62,7 +62,7 @@ public function post(string $uuid, int $signRequestId, ?int $elementId = null, ?
 			'signRequestId' => $signRequestId,
 			'coordinates' => $coordinates,
 			'metadata' => $metadata,
-			'fileUuid' => $uuid,
+			'uuid' => $uuid,
 			'fileId' => $fileId,
 		];
 		try {