fix(pydantic-ai): Safely access tool description attribute

Use getattr with a None default when accessing tool_definition.description
to prevent AttributeError if the attribute is missing.

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

Author: ericapisani

sentry_sdk/integrations/pydantic_ai/spans/execute_tool.py

@@ -39,7 +39,10 @@ def execute_tool_span(
     span.set_data(SPANDATA.GEN_AI_TOOL_NAME, tool_name)
 
     if tool_definition:
-        span.set_data(SPANDATA.GEN_AI_TOOL_DESCRIPTION, tool_definition.description)
+        span.set_data(
+            SPANDATA.GEN_AI_TOOL_DESCRIPTION,
+            getattr(tool_definition, "description", None),
+        )
 
     _set_agent_data(span, agent)