Update lib/HTTP.php

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Signed-off-by: Sebastian Sterk <7263970+sebastiansterk@users.noreply.github.com>

Author: sebastiansterk

lib/HTTP.php

@@ -103,7 +103,7 @@ private function hashPassword($password) {
 	 * @return string|false The username on success, false on failure
 	 */
 	public function checkPassword($uid, $password) {
-		if (isset($uid) && isset($password)) {
+		if (!empty($uid) && !empty($password)) {
 			$authenticationStatus = $this->sendUserData($uid, $password);
 			if ($authenticationStatus) {
 				$uid = mb_strtolower($uid);