fix(sftp): Handle empty port parameter to allow host-defined ports

Signed-off-by: Git'Fellow <12234510+solracsf@users.noreply.github.com>

Author: solracsf

apps/files_external/lib/Lib/Storage/SFTP.php

@@ -68,9 +68,12 @@ public function __construct(array $parameters) {
 		Stream::register();
 
 		$parsedHost = $this->splitHost($parameters['host']);
-
 		$this->host = $parsedHost[0];
-		$this->port = $parameters['port'] ?? $parsedHost[1];
+
+		// Handle empty port parameter to allow host-defined ports
+		// and ensure strictly numeric ports
+		$parsedPort = $parameters['port'] ?? null;
+		$this->port = (int)(is_numeric($parsedPort) ? $parsedPort : $parsedHost[1]);
 
 		if (!isset($parameters['user'])) {
 			throw new \UnexpectedValueException('no authentication parameters specified');