* Adjust margin for sticky elements on modal

Previously white space was visible to the right of sticky elements due to right padding being added to the body. This fixes #23661.

* Add unit tests for margin of sticky elements on modal

element

When one uses say a carousel inside a tab, the `.active` selector previously matches the carousel ones too leading to broken tabs.

It's not the perfect solution but should the job for now.

Ignore ESLint error in ie-emulation-modes-warning.js.

Although the error is valid, enough time has been spent on old IE's problems, so just ignore it.

Part of an update to align the naming schemes across our components.

- Renames .popover-title to .popover-header
- Renames .popover-content to .popover-body

Refs: #22092