Not nullable Boolean fields
### Node Version

23.1.0

### NPM/Yarn/PNPM Version

10.9.0

### Strapi Version

5.4.0

### Operating System

Windows 11

### Database

MySQL

### Bug Description

Boolean fields used to be nullable in version 4, having a "Clear" button to reset it to null, however in version 5 there is no such an option which means that after we set a Boolean value then we cannot make it null again.

Null value could be used as "unknown" in some cases

### Steps to Reproduce

1. Add a Boolean field on a entity
2. Add a value (T/F) on an entry's Boolean field

### Expected Behavior

Having a "Clear" button as an option above Boolean fields so their value could be unset.