Add required output_type attribute to all Tool classes for smolagents 1.9.2 compatibility

tools/final_answer.py

@@ -6,6 +6,7 @@ class FinalAnswerTool(Tool):
     
     name = "final_answer"
     description = "Use this tool to provide your final answer to the user's question."
+    output_type = "string"
     inputs = {
         "answer": {
             "type": "string",

tools/search.py

@@ -8,6 +8,7 @@ class DuckDuckGoSearchTool(Tool):
     
     name = "duck_duck_go_search"
     description = "Search the web for information using DuckDuckGo."
+    output_type = "string"
     inputs = {
         "query": {
             "type": "string",

tools/weather.py

@@ -7,6 +7,7 @@ class WeatherTool(Tool):
     
     name = "get_weather"
     description = "Get the current weather for a specified location."
+    output_type = "string"
     inputs = {
         "location": {
             "type": "string",