MaterialButton TextColor style position problem

## 🐛 Bug Report

I don't know about other cases, but if I set "TextColor" property before "ButtonType" property in my style declaration - the text color is not applied.

### Expected behavior

The "TextColor" property has to be applied independently of the position in the style declaration.

### Reproduction steps

1. Create a simple ContentPage:
```xaml

<Setter Property="TextColor" Value="White" />
<Setter Property="ButtonType" Value="Outlined" />

```

2. Notice the text color is not white:


3. Swap "TextColor" and "ButtonType" properties and notice the color is applied now:
```xaml

<Setter Property="ButtonType" Value="Outlined" />
<Setter Property="TextColor" Value="White" />

```

### Configuration

**Version:** 1.7.8

**Platform:**
- [ ] :iphone: iOS
- [x] :robot: Android
- [ ] :checkered_flag: WPF
- [ ] :earth_americas: UWP
- [ ] :apple: MacOS
- [ ] :tv: tvOS
- [x] :monkey: Xamarin.Forms