Unable to switch to behaviors in a modal when editing paragraphs library item

Problem/Motivation

Steps to reproduce:

- Use experimental paragraph widget with a modal window
- Create a container paragraph
- Create a text paragraph inside the container
- Promote container to library
- Edit library item
- Switch to Behavior tabs

The problem is that `switchActiveClass()` function in paragrpahs.admin.js has an if condition is using `content` and `behavior` id:

if ($parWidget.find('#content').hasClass('is-active')) {
  $parWidget.addClass('content-active');
  $parWidget.find('.paragraphs-add-wrapper').parent().removeClass('hidden');
}
else if ($parWidget.find('#behavior').hasClass('is-active')) {
   $parWidget.addClass('behavior-active');
   $parWidget.find('.paragraphs-add-wrapper').parent().addClass('hidden');
}

and in library modal, we could have two elements with content id:

li#content.tabs__tab
ul#content.paragraphs-add-dialog-list.is-active

This will make this if condition unstable.