[FormBuilderRangeSlider]: Add maxRange value

### Is there an existing issue for this?

- [X] I have searched the existing issues

### Package/Plugin version

9.2.0

### What you'd like to happen

```Markdown
In our flutter project we have your FormBuilderRangeSlider active but there is one issue with it. We want to add a max range of 7, but it seems like that isn't possible. Could it be possible that this can be a thing? With validation i can see when the value is lower than 7 but i cant stop the slider from sliding to like a maxRange of 2 or 5.
```

### Alternatives you've considered

```Markdown
An alternative could be that you can add an minValue and maxValue and make the dots only react to those values. Then it is fully customizable
```

### Aditional information

_No response_