fix(picker): Make highlighted disabled text blue

[mst101]

@MrWook - An easy one!

I noticed that the text colour of highlighted cells remains dark blue even when the cells are disabled - and includeDisabled: true is added to the highlighted config. The muted text also wasn't quite right. You'll see what I mean with the following:

<Datepicker
  placeholder="Select Date"
  :inline="true"
  :disabled-dates="{
    customPredictor: (date) => {
      return date.getDate() % 3 === 0
    },
  }"
  :highlighted="{
    days: [0, 1, 2, 3],
    includeDisabled: true,
  }"
/>

Before:

After: