BHV-17758: moon.Tooltip can not adjust position when absoluteShowing is false

### Issue:
Tooltip is adjust it's position after show.
When tooltip got a requestShow, it try to show itself after 500ms.
But, if it's parent hidden within 500ms and show it again then
tooltip will not able to measure it's position because getAbsoluteBounds will return 0;

### Fix:
Check absoluteShowing just before show tooltip, so it can stop show job when it's parent hidden.

DCO-1.1-Signed-Off-By: Kunmyon Choi kunmyon.choi@lge.com
This could be simplified a bit by moving `show()` into the conditional. Since there's nothing else going on in the method, short circuiting with `return;` isn't adding any value. Also, since this is a private method only triggered by  `requestShow`, it's not necessary to do the existence check on `this.activator` as we know it's been set.

```
if (this.activator.getAbsoluteShowing()) {
    this.show();
}
```