fix: html element id on single element

[Andries-Smit]

HTML Element widget cause error in the log

Warning: Each child in a list should have a unique "key" prop.%s%s See https://reactjs.org/link/warning-keys for more information.%s
at HTMLTag (http://naviva.local:8080/dist/HTMLElement-JMsVPxAr.js:1503:40)

When not using a tagUseRepeat the there is no key set, as item?.id will be empty
This will cause an issues when the the HTML Element widget is placed multiple times in the same parent.

Solution set key to the name of the widget.