fix(admin-controller): align PHPDoc for signature box dimension params

Document that signatureWidth and signatureHeight have a minimum of 1,
matching SIGNATURE_DIMENSION_MINIMUM enforced by SignatureTextService.

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

Author: vitormattos

lib/Controller/AdminController.php

@@ -451,8 +451,8 @@ public function signatureBackgroundDelete(): DataResponse {
 	 * @param string $template Template to signature text
 	 * @param float $templateFontSize Font size used when print the parsed text of this template at PDF file
 	 * @param float $signatureFontSize Font size used when the signature mode is SIGNAME_AND_DESCRIPTION
-	 * @param float $signatureWidth Signature width
-	 * @param float $signatureHeight Signature height
+	 * @param float $signatureWidth Signature box width, minimum 1
+	 * @param float $signatureHeight Signature box height, minimum 1
 	 * @param string $renderMode Signature render mode
 	 * @return DataResponse<Http::STATUS_OK, LibresignSignatureTextSettingsResponse, array{}>|DataResponse<Http::STATUS_BAD_REQUEST, LibresignErrorResponse, array{}>
 	 *