The command-bound event in TapGestureRecognizer points to page instead of viewmodel
## 🐛 Bug Report
Why the event of the command binding in TapGestureRecognizer points to page instead of viewmodel？
<!--- Summary description of the bug --->
`   <StackLayout.GestureRecognizers>
                                <TapGestureRecognizer 
                               Command="{Binding GoToolCommand,Source={x:Reference DiscoverVPage}}"
                               CommandParameter="{Binding .}"/>
                            </StackLayout.GestureRecognizers>`
### Expected behavior

### Reproduction steps

### Configuration

**Version:** 6.x

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