fix(codegen): fix path for copying sts test file (#6148)

Author: siddsriv

codegen/smithy-aws-typescript-codegen/src/main/java/software/amazon/smithy/aws/typescript/codegen/auth/http/integration/AddSTSAuthCustomizations.java

@@ -165,7 +165,7 @@ public void customize(TypeScriptCodegenContext codegenContext) {
             writer.write("export * from $S", "./" + ROLE_ASSUMERS_FILE);
         });
         // test/defaultRoleAssumers.spec.ts
-        writerFactory.accept("test/" + ROLE_ASSUMERS_TEST_FILE + ".spec.ts", writer -> {
+        writerFactory.accept("test/" + ROLE_ASSUMERS_TEST_FILE + ".ts", writer -> {
             String resourceName = STS_CLIENT_PREFIX + ROLE_ASSUMERS_TEST_FILE + ".ts";
             writer
                 .pushState()