Fix for issue #2080 where the GUI appears to hang when a chat with a large

model is deleted. There is no reason to save the context for a chat that
is being deleted.

Signed-off-by: Adam Treat <treat.adam@gmail.com>

gpt4all-chat/chat.cpp

@@ -286,6 +286,11 @@ void Chat::unloadAndDeleteLater()
     unloadModel();
 }
 
+void Chat::markForDeletion()
+{
+    m_llmodel->setMarkedForDeletion(true);
+}
+
 void Chat::unloadModel()
 {
     stopGenerating();