[FormBuilderColorPickerField]: Color labels are not user friendly

### Is there an existing issue for this?

- [x] I have searched the existing issues

### Package/Plugin version

12.0.0

### Platforms

- [x] Android
- [x] iOS
- [ ] Linux
- [ ] MacOS
- [ ] Web
- [ ] Windows

### Flutter doctor

Flutter doctor

```bash
> fvm flutter doctor
Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel stable, 3.29.2, on Arch Linux 6.12.20-1-lts, locale en_US.UTF-8)
[✓] Android toolchain - develop for Android devices (Android SDK version 35.0.0)
[✗] Chrome - develop for the web (Cannot find Chrome executable at google-chrome)
! Cannot find Chrome. Try setting CHROME_EXECUTABLE to a Chrome executable.
[✓] Linux toolchain - develop for Linux desktop
[✓] Android Studio (version 2024.3)
[✓] Connected device (2 available)
[✓] Network resources

! Doctor found issues in 1 category.
```

### Minimal code example

Code sample

```dart
FormBuilderColorPickerField(
name: 'text_color',
initialValue: textColor,
colorPickerType: ColorPickerType.materialPicker,
decoration: const InputDecoration(labelText: 'Text color'),
onChanged: (value) {
if (value != null && value != textColor) {
textColor = value;
onChange();
}
},
),
```

### Current Behavior

The label on each color in the material picker is pretty wild.

Android:


iOS:


### Expected Behavior

A cleaner representation of the color (possibly just the hex value in a smaller text size).

### Steps To Reproduce

Open a color picker

### Aditional information

_No response_