Fix ildaeil crash when carla side has UI disabled

Signed-off-by: falkTX <falktx@falktx.com>

carla

@@ -1 +1 @@
-Subproject commit 33bd1f94b33c53e208bb13d09a567a02976b9f1f
+Subproject commit 6ee03336ab0a15dba4da78dbf7413624228c5db5

dpf

@@ -1 +1 @@
-Subproject commit aa99d51731cf915d83abb578c232b89fbad6c231
+Subproject commit b9e654c3d331933dbeae0413246be8dc2bd64a58

plugins/Cardinal/src/Ildaeil.cpp

@@ -575,11 +575,6 @@ static void host_ui_custom_data_changed(NativeHostHandle handle, const char* key
     d_stdout("%s %p %s %s", __FUNCTION__, handle, key, value);
 }
 
-static void host_ui_closed(NativeHostHandle handle)
-{
-    d_stdout("%s %p", __FUNCTION__, handle);
-}
-
 static const char* host_ui_save_file(NativeHostHandle, bool, const char*, const char*)
 {
     return nullptr;
@@ -806,6 +801,12 @@ struct IldaeilWidget : ImGuiWidget, IdleCallback, Runner {
         setDirty(true);
     }
 
+    void closeUI() noexcept
+    {
+        if (fIdleState == kIdleGiveIdleToUI)
+            fIdleState = kIdleNothing;
+    }
+
     void openFileFromDSP(bool /* isDir */, const char* const title, const char* /* filter */)
     {
         DISTRHO_SAFE_ASSERT_RETURN(idleCallbackActive,);
@@ -1083,7 +1084,8 @@ struct IldaeilWidget : ImGuiWidget, IdleCallback, Runner {
             break;
 
         case kIdleGiveIdleToUI:
-            module->fCarlaPluginDescriptor->ui_idle(module->fCarlaPluginHandle);
+            if (module->fCarlaPluginDescriptor->ui_idle != nullptr)
+                module->fCarlaPluginDescriptor->ui_idle(module->fCarlaPluginHandle);
             break;
 
         case kIdleChangePluginType:
@@ -1634,6 +1636,12 @@ static void host_ui_parameter_changed(const NativeHostHandle handle, const uint3
         ui->changeParameterFromDSP(index, value);
 }
 
+static void host_ui_closed(const NativeHostHandle handle)
+{
+    if (IldaeilWidget* const ui = static_cast<IldaeilWidget*>(static_cast<IldaeilModule*>(handle)->fUI))
+        ui->closeUI();
+}
+
 static const char* host_ui_open_file(const NativeHostHandle handle,
                                      const bool isDir, const char* const title, const char* const filter)
 {