fix(@langchain/google) Duplicate function call (#10493)

Author: afirstenberg

.changeset/tough-facts-cough.md

@@ -0,0 +1,6 @@
+---
+"@langchain/google": patch
+---
+
+Undo regression introduced in #10397 in legacy content processing path.
+Fixes issues with a false duplicate functionCall sent in response (#10474).

libs/providers/langchain-google/src/converters/messages.ts

@@ -736,18 +736,6 @@ function convertLegacyContentMessageToGeminiContent(
     }
   }
 
-  // Convert AIMessage tool_calls to functionCall parts
-  if (AIMessage.isInstance(message) && message.tool_calls?.length) {
-    for (const toolCall of message.tool_calls) {
-      parts.push({
-        functionCall: {
-          name: toolCall.name,
-          args: toolCall.args ?? {},
-        },
-      } as Gemini.Part.FunctionCall);
-    }
-  }
-
   // Handle tool messages as function responses
   if (ToolMessage.isInstance(message) && message.tool_call_id) {
     const responseContent =