DeepClone does not clone java.util.Date fields but perform a copy reference

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### Expected behavior

I have a mapper annotated DeepClone to perform a copy clone of some bean. I notice that the generated implementation on java.util.Date field it perform a simple `a.setDate(b.getDate())`. This could be ok for String or BigDecimal object that are immutable but old java Date object are not immutable that mean if I change `b.getDate().setTime(1l)` it will also update date in the bean a.

What I expect is that in case of DeepClone it produce the following code:
```
@Override
public BeanA clone(BeanA value) {
if ( value == null ) {
return null;
}

BeanA beanA = new BeanA();
if (source.getDate() != null) {
beanA.setDate(new Date(source.getDate().getTime())); // expected behaviour
}

return beanA;
}
```

### Actual behavior

The generated code is
```
@Generated(
value = "org.mapstruct.ap.MappingProcessor",
date = "2025-09-16T10:12:55+0200",
comments = "version: 1.6.3, compiler: Eclipse JDT (IDE) 3.41.0.v20250213-1140, environment: Java 21.0.6 (Eclipse Adoptium)"
)
public class ICloneMapperImpl implements ICloneMapper {

@Override
public BeanA clone(BeanA value) {
if ( value == null ) {
return null;
}

BeanA beanA = new BeanA();
beanA.setDate(source.getDate());

return beanA;
}
}
```

### Steps to reproduce the problem

Create the following classes
```
public class BeanA {
private Date date;
public Date getDate() { return date; }
public void setDate(Date value) { date = value; }
}

@Mapper(mappingControl = DeepClone.class)
public interface ICloneMapper {
BeanA clone(BeanA source);
}
```

### MapStruct Version

MapStruct 1.6.3

### Workaround

In the ICloneMapper I have to define a method like this:
```
default Date map(Date value) {
return value != null ? new Date(value.getTime()) : null;
}
```
to get the clone of date.

Start with the DeepClone mapping control and the ICloneMapper reproduction shown in the issue. Check how the generated mapper handles java.util.Date fields; done means the generated clone does not share the mutable Date reference, including when the original date is later changed.

Written by the indexing model from the issue text.