Environment
Provide version numbers for the following components (information can be retrieved by running tns info in your project folder or by inspecting the package.json of the project):

• CLI: 5.2.0
• Cross-platform modules: ~5.1.0
• Android Runtime: 5.1.0
• iOS Runtime: 5.1.1
• Plugin(s):
• NativeScript-Angular: ~7.1.0
• Angular: ~7.1.0

Describe the bug
Declaring an ListView without defining a specific ng-template causes exception when the ListView is scrolled.

To Reproduce

<ListView [items]="pickerItems" (itemTap)="onItemTap($event)" class="list-group" row="1">
    
</ListView>

Expected behavior
Declaring an ListView without defining a specific ng-template will show the list with the default (Label) item template and will not crash after scrolling it.