rename synthetic error namespace to smithy (smithy-lang#1611)

Author: kuhe

smithy-typescript-codegen/src/main/java/software/amazon/smithy/typescript/codegen/schema/SchemaGenerator.java

@@ -275,7 +275,7 @@ private void writeBaseError() {
         writer.write("""
                 export var $L = error($S, $S, 0, [], []""",
             serviceExceptionName,
-            "awssdkjs.synthetic." + namespace,
+            "smithy.ts.sdk.synthetic." + namespace,
             serviceExceptionName
         );
         writer.writeInline(",$L", exceptionCtorSymbolName);