Fix MapStruct maven plugin warnings

[arey]

There are some unmapped target properties:

[INFO] Compiling 112 source files with javac [debug parameters release 17] to target/classes
[WARNING] /Users/arey/Dev/GitHub/spring-petclinic/spring-petclinic-rest/src/main/java/org/springframework/samples/petclinic/mapper/PetTypeMapper.java:[19,13] Unmapped target property: "id".
[WARNING] /Users/arey/Dev/GitHub/spring-petclinic/spring-petclinic-rest/src/main/java/org/springframework/samples/petclinic/mapper/VetMapper.java:[17,9] Unmapped target property: "id".
[WARNING] /Users/arey/Dev/GitHub/spring-petclinic/spring-petclinic-rest/src/main/java/org/springframework/samples/petclinic/mapper/VisitMapper.java:[16,11] Unmapped target property: "pet".
[WARNING] /Users/arey/Dev/GitHub/spring-petclinic/spring-petclinic-rest/src/main/java/org/springframework/samples/petclinic/mapper/VisitMapper.java:[18,11] Unmapped target properties: "id, pet".
[WARNING] /Users/arey/Dev/GitHub/spring-petclinic/spring-petclinic-rest/src/main/java/org/springframework/samples/petclinic/mapper/PetMapper.java:[20,12] Unmapped target property: "petId". Mapping from Collection element "Visit visits" to "VisitDto visits".
[WARNING] /Users/arey/Dev/GitHub/spring-petclinic/spring-petclinic-rest/src/main/java/org/springframework/samples/petclinic/mapper/PetMapper.java:[26,9] Unmapped target property: "pet". Mapping from Collection element "VisitDto visits" to "Visit visits".
[WARNING] /Users/arey/Dev/GitHub/spring-petclinic/spring-petclinic-rest/src/main/java/org/springframework/samples/petclinic/mapper/PetMapper.java:[26,9] Unmapped target property: "owner".
[WARNING] /Users/arey/Dev/GitHub/spring-petclinic/spring-petclinic-rest/src/main/java/org/springframework/samples/petclinic/mapper/PetMapper.java:[28,9] Unmapped target properties: "id, owner, visits".
[WARNING] /Users/arey/Dev/GitHub/spring-petclinic/spring-petclinic-rest/src/main/java/org/springframework/samples/petclinic/mapper/OwnerMapper.java:[21,11] Unmapped target properties: "id, pets".
[WARNING] /Users/arey/Dev/GitHub/spring-petclinic/spring-petclinic-rest/src/main/java/org/springframework/samples/petclinic/mapper/UserMapper.java:[16,10] Unmapped target properties: "id, user".
[INFO] 

[joaobertholino]

Hello, how are you?
I'm new here, I took a look at this issue #157, and I verified that the cause of the warnings is due to the fact that the object received as an argument does not have the attributes indicated as "not mapped" in the log message, thus resulting in a warning.

If the lack of these attributes is intentional, one way to hide these warnings in the log would be to implement a specific reporting policy to ignore attributes not mapped by MapStruct.