Add missing import in test input

Following openrewrite/rewrite#4406

src/testWithSpringBoot_2_1/java/org/openrewrite/java/spring/ImplicitWebAnnotationNamesTest.java

@@ -169,6 +169,7 @@ void doesNotRenamePathVariable() {
         rewriteRun(
           java(
             """
+              import org.springframework.http.ResponseEntity;
               import org.springframework.web.bind.annotation.*;
               
               public class UsersController {