fix model parameter (#1303)

LGTM

Author: maekawataiki

packages/cdk/lambda/utils/models.ts

@@ -112,7 +112,6 @@ const CLAUDE_4_5_DEFAULT_PARAMS: ConverseInferenceParams = {
   inferenceConfig: {
     maxTokens: 64000,
     temperature: 1,
-    topK: 250,
   },
 };