update basetool dependencies to use root crewai repo

src/crewai_tools/tools/exa_tools/exa_base_tool.py

@@ -1,10 +1,8 @@
-import os
 from typing import Type
 
+from crewai.tools import BaseTool
 from pydantic import BaseModel, Field
 
-from crewai_tools.tools.base_tool import BaseTool
-
 
 class EXABaseToolToolSchema(BaseModel):
     """Input for EXABaseTool."""