refactor: drop json attributes in Pet entity

src/main/java/org/springframework/samples/petclinic/model/Pet.java

@@ -37,9 +37,6 @@ import org.springframework.beans.support.MutableSortDefinition;
 import org.springframework.beans.support.PropertyComparator;
 import org.springframework.format.annotation.DateTimeFormat;
 
-import com.fasterxml.jackson.annotation.JsonIgnore;
-import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
-import com.fasterxml.jackson.databind.annotation.JsonSerialize;
 
 /**
  * Simple business object representing a pet.
@@ -92,7 +89,7 @@ public class Pet extends NamedEntity {
     public void setOwner(Owner owner) {
         this.owner = owner;
     }
-    @JsonIgnore
+
     protected Set<Visit> getVisitsInternal() {
         if (this.visits == null) {
             this.visits = new HashSet<>();