[Renderer] AttributePart failed to handle strings with interpolation

[KinG-DE]

If I use Links in my templates, like

<a href="whatsapp://send?text=${this.shareLink}">Link Label 1</a>

I got an javascript error

Its looks like, the AttritubePart has problems with strings containing interpolations.

https://codepen.io/KingDE/pen/NPGyVjO?editors=1010

[quarkus]

I added a failing test to the linked branch @eddyloewen .

Im am pretty sure its just a split on the wrong "=" as name and value get mixed up but i cannot find the place where it happens.

[eddyloewen]

I'm pretty sure that we fixed the problem with splitting the "=" signs inside attributes. But from looking at the code where that happens, it might be that the "?" could be the problem here:
https://github.com/webtides/element-js/blob/main/src/dom-parts/TemplateResult.js#L409
And also here:
https://github.com/webtides/element-js/blob/main/src/dom-parts/TemplateResult.js#L422