fix: abstract_graph moel token bug

Author: VinciGit00

scrapegraphai/graphs/abstract_graph.py

@@ -148,6 +148,10 @@ def _create_llm(self, llm_config: dict, chat=False) -> object:
 
         # If model instance is passed directly instead of the model details
         if "model_instance" in llm_params:
+            try:
+               self.model_token = llm_params["model_tokens"]
+            except KeyError as exc:
+               raise KeyError("model_tokens not specified") from exc
             return llm_params["model_instance"]
 
         # Instantiate the language model based on the model name