Fix PetValidator when using the JDBC profile

Steps to reproduce:
Set the web.xml context-param spring.profiles.active to jdbc.
Run app and navigate to Find owners > Find Owner > Betty Davis > Edit
Pet.
Notice the java.lang.IllegalStateException: Invalid target for Validator
[org.springframework.samples.petclinic.web.PetValidator@213eb80d]: Basil

src/main/java/org/springframework/samples/petclinic/web/PetValidator.java

@@ -58,7 +58,7 @@ public class PetValidator implements Validator {
      */
     @Override
     public boolean supports(Class<?> clazz) {
-        return Pet.class.equals(clazz);
+        return Pet.class.isAssignableFrom(clazz);
     }