[ic-popover] @Watch on dynamic slots

## Summary
Create a @Watch that ensures dynamically slotted popover elements are rendered correctly.

## 💬 Description
If a new popover element is dynamically slotted ensure that the `theme` is inline with parent, among other rendering issues.

Start by locating the popover component and its existing @Watch usage, then reproduce a dynamically slotted popover to inspect the rendering behavior described. Done means newly slotted popovers render correctly, including a theme inline with the parent and any other rendering issues identified during reproduction.

Written by the indexing model from the issue text.