HorizontalContentAlignment of ListBox in AutoSuggestBox #3939

<materialDesign:AutoSuggestBox Margin="{StaticResource DefaultSpacing}"
                               HorizontalAlignment="Stretch"
                               materialDesign:HintAssist.Hint="Username or E-Mail"
                               materialDesign:TextFieldAssist.HasLeadingIcon="True"
                               materialDesign:TextFieldAssist.LeadingIcon="User"
                               DropDownBackground="{DynamicResource MaterialDesign.Brush.ToolBar.Background}"
                               DropDownElevation="Dp24"
                               DropDownMaxHeight="500"
                               Suggestions="{Binding EmailSuggestions}"
                               Text="{Binding Email, UpdateSourceTrigger=PropertyChanged}">
  <materialDesign:AutoSuggestBox.InputBindings>
    <KeyBinding Key="Enter" Command="{Binding LoginCommand}" />
  </materialDesign:AutoSuggestBox.InputBindings>
  <materialDesign:AutoSuggestBox.ItemTemplate>
    <DataTemplate>
      <Grid HorizontalAlignment="Stretch" utils:GridAssist.Columns="*, auto" Background="Fuchsia">
        <TextBlock Grid.Column="0" Text="{Binding .}" VerticalAlignment="Center" />
        <Button Grid.Column="1"
                Padding="2,0,0,0"
                Command="{Binding DataContext.RemoveSuggestion, RelativeSource={RelativeSource AncestorType=UserControl}}"
                Focusable="False"
                Style="{StaticResource MaterialDesignToolButton}">
          <materialDesign:PackIcon Width="16"
                                   Height="16"
                                   Margin="0"
                                   Kind="CloseCircle" />
        </Button>
      </Grid>
    </DataTemplate>
  </materialDesign:AutoSuggestBox.ItemTemplate>
</materialDesign:AutoSuggestBox>