fix for signup router

frontend/pweb/lib/pages/login/form.dart

@@ -109,7 +109,7 @@ class _LoginFormState extends State<LoginForm> {
             builder: (context, isUsernameValid, child) => ValueListenableBuilder<bool>(
               valueListenable: _isPasswordAcceptable,
               builder: (context, isPasswordValid, child) => ButtonsRow(
-                onSignUp: () => navigate(context, Pages.signup),
+                onSignUp: () => navigateAndReplace(context, Pages.signup),
                 login: () => _login(
                   context, 
                   () => navigateAndReplace(context, Pages.dashboard),

frontend/pweb/lib/pages/signup/form/content.dart

@@ -34,7 +34,7 @@ class SignUpFormContent extends StatelessWidget {
               Row(
                 children: [
                   IconButton(
-                    onPressed: Navigator.of(context).pop,
+                    onPressed: onLogin,
                     icon: Icon(Icons.arrow_back),
                   ),
                 ],
@@ -59,4 +59,4 @@ class SignUpFormContent extends StatelessWidget {
       ),
     ),
   );
-}
+}

frontend/pweb/lib/pages/signup/form/state.dart

@@ -105,7 +105,7 @@ class SignUpFormState extends State<SignUpForm> {
         ),
       );
 
-  void handleLogin() => navigate(context, Pages.login);
+  void handleLogin() => navigateAndReplace(context, Pages.login);
 
   @override
   void dispose() {