FIX: theme_m22tc: add hidden login field for invitation signup to prevent 500 error

theme_m22tc/views/login_custom.xml

@@ -241,6 +241,9 @@
                                            autofocus="autofocus" autocapitalize="off"
                                            t-att-readonly="'readonly' if (token and not invalid_token) else None"/>
                                 </div>
+                                <div t-else="">
+                                  <input type="hidden" name="login" t-att-value="login"/>
+                                </div>
 
                                 <!-- Password Input -->
                                 <div>