RNMobile: Slider and stepper text inputs not rendering correct color in dark mode

[guarani]

Description

The slider control colours are off. (Particularly the part that displays the number)
You can replicate this by looking using the slider in the spacer block but it is also found in other block settings such as button and column.

Step-by-step reproduction instructions

1. Run the demo app on an iOS device
2. Switch the device to dark mode
3. Add a spacer block or any other block that uses sliders or steppers
4. Notice that the text input next to the slider or stepper has black text instead of white

Expected behaviour

In dark mode, the slider and stepper text fields should have white text.

Actual behaviour

In dark mode, the slider and stepper text fields has dark text, making it hard to read.

Screenshots or screen recording (optional)

Device information

• Device: iPhone 12
• Operating system: iOS 14.5