fix(SignFileService): include placed elements when signer submits no image

When canCreateSignature is true but the signer performs a clickToSign
(no drawn image submitted), the DB file element was silently skipped,
producing an empty visibleElements list and no stamp on the document.
Include the element with an empty tempFile so the admin background
image (n0 layer) is still rendered in the signature stamp.

Signed-off-by: Vitor Mattos <1079143+vitormattos@users.noreply.github.com>

Author: vitormattos

lib/Service/SignFileService.php

@@ -286,6 +286,10 @@ public function setVisibleElements(array $list): self {
 			}
 			$element = $this->array_find($list, fn (array $element): bool => ($element['documentElementId'] ?? '') === $fileElementId);
 			if (!$element) {
+				// No user-submitted image for this element (e.g. clickToSign).
+				// Still include the file element so the admin background image (n0 layer)
+				// is rendered in the signature stamp on the document.
+				$newElements[$fileElementId] = new VisibleElementAssoc($fileElement);
 				continue;
 			}
 			$nodeId = $this->getNodeId($element, $fileElement);