Button clicks dont work on mobile devices for nested components

[aandis]

Describe the bug
If the item inside {{#item.handle}} or {{#group.item}} is an ember component with buttons, button clicks dont work on mobile devices.

To Reproduce
Steps to reproduce the behavior:

1. Go to twiddle.
2. Simulate mobile device on Chrome/Desktop or try it out on a real mobile device.
3. Try clicking the buttons.

Expected behavior
Button clicks and other touch events should work on mobile devices.

Carried over from #339

[MathijsPeerlings]

Is there already a proposed solution for this?

[NullVoxPopuli]

Not that i've seen. A PR would be most helpful!

[BvG-Gynzy]

Skipping the preventDefault for touchstart works for me.

    if (startEvent.type !== 'touchstart') {
      //click event (touch) of child elements is prevented by the following line
      startEvent.preventDefault();
    }

Also _preventClick should be skipped for touch, otherwise clicking after drop does not work the first time.

    const isTouch = event.type === 'touchstart';
    this._drop(isTouch);
    if (!isTouch) {
      this._preventClick();
    }

Will create PR later.