fix(anthropic): fix Sonnet 4.5 context management (langchain-ai#9141)

Co-authored-by: Hunter Lovell <hunter@hntrl.io>
Co-authored-by: Hunter Lovell <40191806+hntrl@users.noreply.github.com>

Author: jlguerreiro

.changeset/fast-peas-lick.md

@@ -0,0 +1,5 @@
+---
+"@langchain/anthropic": patch
+---
+
+fix content management param

libs/langchain-anthropic/src/chat_models.ts

@@ -753,6 +753,8 @@ export class ChatAnthropicMessages<
     this.streamUsage = fields?.streamUsage ?? this.streamUsage;
 
     this.thinking = fields?.thinking ?? this.thinking;
+    this.contextManagement =
+      fields?.contextManagement ?? this.contextManagement;
 
     this.createClient =
       fields?.createClient ??