fix issue when discriminator property is an enum string (#13001)

samples/client/petstore/java/okhttp-gson-group-parameter/src/main/java/org/openapitools/client/model/Category.java

@@ -58,7 +58,7 @@ public class Category {
   @SerializedName(SERIALIZED_NAME_NAME)
   private String name;
 
-  public Category() { 
+  public Category() {
   }
 
   public Category id(Long id) {

samples/client/petstore/java/okhttp-gson-group-parameter/src/main/java/org/openapitools/client/model/ModelApiResponse.java

@@ -62,7 +62,7 @@ public class ModelApiResponse {
   @SerializedName(SERIALIZED_NAME_MESSAGE)
   private String message;
 
-  public ModelApiResponse() { 
+  public ModelApiResponse() {
   }
 
   public ModelApiResponse code(Integer code) {

samples/client/petstore/java/okhttp-gson-group-parameter/src/main/java/org/openapitools/client/model/Order.java

@@ -124,7 +124,7 @@ public class Order {
   @SerializedName(SERIALIZED_NAME_COMPLETE)
   private Boolean complete = false;
 
-  public Order() { 
+  public Order() {
   }
 
   public Order id(Long id) {

samples/client/petstore/java/okhttp-gson-group-parameter/src/main/java/org/openapitools/client/model/Pet.java

@@ -127,7 +127,7 @@ public class Pet {
   @SerializedName(SERIALIZED_NAME_STATUS)
   private StatusEnum status;
 
-  public Pet() { 
+  public Pet() {
   }
 
   public Pet id(Long id) {

samples/client/petstore/java/okhttp-gson-group-parameter/src/main/java/org/openapitools/client/model/Tag.java

@@ -58,7 +58,7 @@ public class Tag {
   @SerializedName(SERIALIZED_NAME_NAME)
   private String name;
 
-  public Tag() { 
+  public Tag() {
   }
 
   public Tag id(Long id) {

samples/client/petstore/java/okhttp-gson-group-parameter/src/main/java/org/openapitools/client/model/User.java

@@ -82,7 +82,7 @@ public class User {
   @SerializedName(SERIALIZED_NAME_USER_STATUS)
   private Integer userStatus;
 
-  public User() { 
+  public User() {
   }
 
   public User id(Long id) {