Item Undefined in suggestion Popover

[allen138]

Describe the bug
When using ui5-li-custom to build a custom list item to insert into the suggestion popover via the hbs partial added here: #1928, and when you select the item from the suggestion popover, "item" is undefined. Upon further investigation, onItemSelected will call this._getItems() which only does querySelectorAll("ui5-li, ui5-li-groupheader"). This may also be a side effect as well, but I am unable to arrow into the suggestion popover as it seems this functionality relies on this._getItems().

To reproduce
Steps to reproduce the behavior:

1. Clone "@xweb/common-webcomponents"
2. Pull branch "feature/personInput"
3. Install, start and open "http://localhost:8081/test-resources/pages/PersonInput.html"
4. Open "CustomInput.hbs" and switch between ui5-li-custom and ui5-li to observe the different behavior
5. In the "Default Person Search" input, type "aa".
6. Notice you cannot arrow into the suggestedItems
7. Click one of the items and notice the error in the js console.

Expected behavior
With the newly hbs partial added, functionality should be the same for ui5-li-custom as for ui5-li

Screenshots

Context

• UI5 Web Components version: 0.21.8
• OS/Platform: Windows 10
• Browser (if relevant): All