Add more concatenateUris test. Fix joining params

packages/go_router/lib/src/path_utils.dart

@@ -125,7 +125,7 @@ String concatenatePaths(String parentPath, String childPath) {
 Uri concatenateUris(Uri parentUri, Uri childUri) {
   // Merge query parameters from both Uris. We don't return an empty map to prevent trailing '?'.
   final Map<String, dynamic>? newParameters =
-      parentUri.queryParameters.isNotEmpty &&
+      parentUri.queryParameters.isNotEmpty ||
               childUri.queryParameters.isNotEmpty
           ? <String, dynamic>{
               ...parentUri.queryParameters,

packages/go_router/test/path_utils_test.dart

@@ -102,6 +102,10 @@ void main() {
 
     verify('/a', 'b/c', '/a/b/c');
     verify('/', 'b', '/b');
+
+    // Test with parameters
+    verify('/a?fid=f1', 'b/c', '/a/b/c?fid=f1');
+    verify('/a', 'b/c?pid=p2', '/a/b/c?pid=p2');
     verify('/a?fid=f1', 'b/c?pid=p2', '/a/b/c?fid=f1&pid=p2');
   });