Replace ColorEntry with ExprEntry in Color Sliders

[Akylzhan]

Adds #3900

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[dacap]

Hi @Akylzhan, thanks for your PR. Probably we require a different approach for this. Probably just changing:

class ColorEntry : public ExprEntry

[Akylzhan]

@dacap Yes, you are right. Did not think about that. Changed ColorEntry's base to ExprEntry

[dacap]

Thanks @Akylzhan, I've just merged this change in 3e171d0 with a missing setText("0") so the entry fields start with 0 in the Edit > Adjustments > Hue/Saturation dialog.