Fix an issue with the button's activity indicator

Author: AgustinBonilla

MaterialDesignControls.nuspec

@@ -2,7 +2,7 @@
 <package xmlns="http://schemas.microsoft.com/packaging/2010/07/nuspec.xsd">
    <metadata minClientVersion="2.8.1">
        <id>Plugin.MaterialDesignControls</id>
-       <version>1.10.1</version>
+       <version>1.10.2</version>
        <title>MaterialDesignControls Plugin for Xamarin Forms</title>
        <authors>Horus</authors>
        <owners>AgustinBonillaHorus</owners>

src/MaterialDesignControls/Controls/MaterialButton.cs

@@ -333,7 +333,7 @@ private void Initialize()
             cntActivityIndicator = new ContentView
             {
                 VerticalOptions = LayoutOptions.Center,
-                HorizontalOptions = LayoutOptions.Center,
+                HorizontalOptions = LayoutOptions.CenterAndExpand,
                 WidthRequest = ActivityIndicatorSize,
                 HeightRequest = ActivityIndicatorSize,
                 IsVisible = false