chore: remove unecessary check if node exists

The method get already do this and throw an exception when the file
don't exists.

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

Author: vitormattos

lib/Handler/SignEngine/SignEngineHandler.php

@@ -180,14 +180,11 @@ public function getPfxOfCurrentSigner(?string $uid = null): string {
 		}
 		$this->folderService->setUserId($uid);
 		$folder = $this->folderService->getFolder();
-		if (!$folder->nodeExists($this->pfxFilename)) {
-			throw new LibresignException($this->l10n->t('Password to sign not defined. Create a password to sign.'), 400);
-		}
 		try {
 			/** @var \OCP\Files\File */
 			$node = $folder->get($this->pfxFilename);
 			$this->certificate = $node->getContent();
-		} catch (GenericFileException) {
+		} catch (GenericFileException|NotFoundException) {
 			throw new LibresignException($this->l10n->t('Password to sign not defined. Create a password to sign.'), 400);
 		} catch (\Throwable) {
 		}