chore: disable idempotency autofill import when not generating a client (aws#2181)

Author: adamthom-amzn

codegen/smithy-aws-typescript-codegen/src/main/java/software/amazon/smithy/aws/typescript/codegen/AwsProtocolUtils.java

@@ -221,6 +221,10 @@ static boolean writeXmlNamespace(GenerationContext context, Shape shape, String
      * @param context The generation context.
      */
     static void addItempotencyAutofillImport(GenerationContext context) {
+        // servers do not autogenerate idempotency tokens during deserialization
+        if (!context.getSettings().generateClient()) {
+            return;
+        }
         context.getModel().shapes(MemberShape.class)
                 .filter(memberShape -> memberShape.hasTrait(IdempotencyTokenTrait.class))
                 .findFirst()