Add helpful print statements and fix isURL validation

frontend/lib/utils/uri_utility.dart

@@ -2,11 +2,13 @@ class UriUtility {
   static bool isURL(String url) {
     // Validate if the URL string is empty, or contains spaces or invalid characters
     if (url.isEmpty || RegExp(r'[\s<>]').hasMatch(url)) {
+      print('URL is either empty or contains spaces/invalid characters.');
       return false;
     }
 
     // Check for 'mailto:' at the start of the URL
     if (url.startsWith('mailto:')) {
+      print('URL starts with "mailto:".');
       return false;
     }
 
@@ -15,26 +17,31 @@ class UriUtility {
     try {
       uri = Uri.parse(url);
     } catch (e) {
+      print('URL parsing failed: $e');
       return false;
     }
 
     // Validate the URL has a scheme (protocol) and host
     if (uri.scheme.isEmpty || uri.host.isEmpty) {
+      print('URL is missing a scheme (protocol) or host.');
       return false;
     }
 
     // Check if the URI has user info, which is not a common case for a valid HTTP/HTTPS URL
     if (uri.hasAuthority &&
-        (uri.userInfo.isEmpty ||
-            uri.userInfo.contains(':') && uri.userInfo.split(':').length > 2)) {
+        uri.userInfo.contains(':') &&
+        uri.userInfo.split(':').length > 2) {
+      print('URL contains invalid user info.');
       return false;
     }
 
     // Validate the port number if exists
     if (uri.hasPort && (uri.port <= 0 || uri.port > 65535)) {
+      print('URL contains an invalid port number.');
       return false;
     }
 
+    print('URL is valid.');
     return true;
   }
 }