fix: psalm errors

Signed-off-by: Vitor Mattos <vitor@php.rio>

Author: vitormattos

lib/Service/Install/InstallService.php

@@ -310,7 +310,7 @@ public function setResource(string $resource): self {
 	public function installJava(?bool $async = false): void {
 		$signatureEngine = $this->appConfig->getAppValue('signature_engine', 'jsignpdf');
 		if ($signatureEngine !== 'jsignpdf') {
-			return [];
+			return;
 		}
 		$this->setResource('java');
 		if ($async) {
@@ -384,7 +384,7 @@ public function uninstallJava(): void {
 	public function installJSignPdf(?bool $async = false): void {
 		$signatureEngine = $this->appConfig->getAppValue('signature_engine', 'jsignpdf');
 		if ($signatureEngine !== 'jsignpdf') {
-			return [];
+			return;
 		}
 		if (!extension_loaded('zip')) {
 			throw new RuntimeException('Zip extension is not available');