Sets or gets the value of the slider. value is not bound by the min or
max values set for the slider.
Notes:
- Changing a slider's value in code does not trigger an onChange event.
- If a slider is connected to a dataset, setting the slider's value in code
does not set the value of the connected field in the dataset. That means if
you use the dataset to perform a submit, the value changed in code is not
reflected in the submitted item.
- To submit the new value using a dataset, set the field's value using
the setFieldValue() function before
performing the submit.