fix: add default value for new flag `$useDecryptAll` on getFileKey

Signed-off-by: Côme Chilliet <come.chilliet@nextcloud.com>

apps/encryption/lib/KeyManager.php

@@ -345,7 +345,7 @@ class KeyManager {
 	/**
 	 * @param ?bool $useLegacyFileKey null means try both
 	 */
-	public function getFileKey(string $path, ?string $uid, ?bool $useLegacyFileKey, bool $useDecryptAll): string {
+	public function getFileKey(string $path, ?string $uid, ?bool $useLegacyFileKey, bool $useDecryptAll = false): string {
 		if ($uid === '') {
 			$uid = null;
 		}