message: fix(popover): added a space between containerClass and checkMarginNecessity()
  If checkMarginNecessity() returns anything, it breaks the containerClass, since there's no spacing between the classes
diff: @@ -10,7 +10,7 @@ import { PlacementForBs5, checkMargins, AvailbleBSPositions } from 'ngx-bootstra
  host: {
  '[attr.id]': 'popoverId',
  '[class]':
  - '"popover in popover-" + _placement + " " + "bs-popover-" + _placement + " " + _placement + " " + containerClass + checkMarginNecessity()',
  + '"popover in popover-" + _placement + " " + "bs-popover-" + _placement + " " + _placement + " " + containerClass + " " + checkMarginNecessity()',
  '[class.show]': '!_bsVersions.isBs3',
  '[class.bs3]': '_bsVersions.isBs3',
  role: 'tooltip',
  