bug: Slider Input widget colour leaves the label white

[ES-Alexander]

Bug description

The Slider Input widget has a label to describe what it does, but changing the widget's colour configuration only changes it for the slider itself, not the label, and there's no option to change the label colour.

Steps to reproduce

1. Open Edit Mode
2. Add a Custom Base
3. Add a Slider input widget
4. Change its colour
5. The label stays the same

Primary pain point(s)

Usually the colour is changed for a reason, and white for the label text may not be readable.

Additional context

It seems like they should either be set to:

1. consistently the same colour,
2. individually controlled colours, or
3. individual colours with a checkbox to share the colour

Prerequisites

• I have checked to make sure that a similar request has not already been filed or fixed.