[Bug]: on iOS, when the value of a property is null, the default Text of a label is no longer overwritten
### Description

When the value of a binding property in iOS is null, and you try to bind that to the text of a label. Is it now no no longer setting the text to empty on that label? 
And with that I mean:
set.Bind(this.LabelNamePostfix).To(dv => dv.NamePostfix);
If db.NamePostfix ==  null, the default text on LabelNamePostfix is no longer overwritten.

This means that the Default text on that label from the storyboard will remain visible.

### Steps to Reproduce

Step 1: Have a label on your view and make it have default text.
Step 2: Bind the label to a nullable property with the value null.

### Link to public reproduction project repository

_No response_

### Version with bug

9.2.0

### Is this a regression from previous behavior?

Yes, this used to work in a previous version

### Last version that worked well

8.0.0

### Affected platforms

iOS/MacCatalyst

### Affected platform versions

_No response_

### Did you find any workaround?

No.