Switch order of literals to prevent NullPointerException (#2035)

Co-authored-by: pixeebot[bot] <104101892+pixeebot[bot]@users.noreply.github.com>

src/main/java/stirling/software/SPDF/SPdfApplication.java

@@ -37,7 +37,7 @@ public class SPdfApplication {
 
     @Value("${server.port:8080}")
     public void setServerPortStatic(String port) {
-        if (port.equalsIgnoreCase("auto")) {
+        if ("auto".equalsIgnoreCase(port)) {
             // Use Spring Boot's automatic port assignment (server.port=0)
             SPdfApplication.serverPortStatic =
                     "0"; // This will let Spring Boot assign an available port