Use chat_model specified in new offline_chat section of config

- Dedupe offline_chat_model variable. Only reference offline chat
  model stored under offline_chat. Delete the previous chat_model
  field under GPT4AllProcessorConfig

- Set offline chat model to use via config/offline_chat API endpoint

src/khoj/routers/api.py

@@ -288,6 +288,7 @@ if not state.demo:
     async def set_processor_enable_offline_chat_config_data(
         request: Request,
         enable_offline_chat: bool,
+        offline_chat_model: Optional[str] = None,
         client: Optional[str] = None,
     ):
         _initialize_config()
@@ -302,6 +303,8 @@ if not state.demo:
 
         assert state.config.processor.conversation is not None
         state.config.processor.conversation.offline_chat.enable_offline_chat = enable_offline_chat
+        if offline_chat_model is not None:
+            state.config.processor.conversation.offline_chat.chat_model = offline_chat_model
         state.processor_config = configure_processor(state.config.processor, state.processor_config)
 
         update_telemetry_state(

src/khoj/routers/helpers.py

@@ -122,7 +122,7 @@ def generate_chat_response(
                 conversation_log=meta_log,
                 completion_func=partial_completion,
                 conversation_command=conversation_command,
-                model=state.processor_config.conversation.gpt4all_model.chat_model,
+                model=state.processor_config.conversation.offline_chat.chat_model,
             )
 
         elif state.processor_config.conversation.openai_model:

src/khoj/utils/config.py

@@ -84,7 +84,6 @@ class SearchModels:
 
 @dataclass
 class GPT4AllProcessorConfig:
-    chat_model: Optional[str] = None
     loaded_model: Union[Any, None] = None
 
 
@@ -95,7 +94,6 @@ class ConversationProcessorConfigModel:
     ):
         self.openai_model = conversation_config.openai
         self.gpt4all_model = GPT4AllProcessorConfig()
-        self.gpt4all_model.chat_model = conversation_config.offline_chat_model
         self.offline_chat = conversation_config.offline_chat
         self.conversation_logfile = Path(conversation_config.conversation_logfile)
         self.chat_session: List[str] = []
@@ -103,7 +101,7 @@ class ConversationProcessorConfigModel:
 
         if self.offline_chat.enable_offline_chat:
             try:
-                self.gpt4all_model.loaded_model = download_model(self.gpt4all_model.chat_model)
+                self.gpt4all_model.loaded_model = download_model(self.offline_chat.chat_model)
             except ValueError as e:
                 self.offline_chat.enable_offline_chat = False
                 self.gpt4all_model.loaded_model = None