Avoid updating _lastChange when nothing is changed in the configuration

Had to set at least one var when creating an empty configuration in
 order to save the default values.

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

apps/user_ldap/lib/Command/CreateEmptyConfig.php

@@ -59,6 +59,7 @@ protected function configure() {
 	protected function execute(InputInterface $input, OutputInterface $output): int {
 		$configPrefix = $this->helper->getNextServerConfigurationPrefix();
 		$configHolder = new Configuration($configPrefix);
+		$configHolder->ldapConfigurationActive = false;
 		$configHolder->saveConfiguration();
 
 		$prose = '';

apps/user_ldap/lib/Configuration.php

@@ -56,10 +56,9 @@ class Configuration {
 	 */
 	protected $configRead = false;
 	/**
-	 * @var string[] pre-filled with one reference key so that at least one entry is written on save request and
-	 *               the config ID is registered
+	 * @var string[]
 	 */
-	protected $unsavedChanges = ['ldapConfigurationActive' => 'ldapConfigurationActive'];
+	protected array $unsavedChanges = [];
 
 	/**
 	 * @var array<string, mixed> settings

apps/user_ldap/lib/Controller/ConfigAPIController.php

@@ -118,6 +118,7 @@ public function create() {
 		try {
 			$configPrefix = $this->ldapHelper->getNextServerConfigurationPrefix();
 			$configHolder = new Configuration($configPrefix);
+			$configHolder->ldapConfigurationActive = false;
 			$configHolder->saveConfiguration();
 		} catch (\Exception $e) {
 			$this->logger->logException($e);