Fixed Firefox not respecting default selected operator when changing filter type
Fixed Firefox not respecting default selected operator when changing filter type

no issue

- if `<option>` elements are re-rendered without the parent `<select>` being re-rendered, Firefox does not pick up the new `selected` option
  - we were seeing this behaviour when the options in an operator select get updated after changing the filter type, Firefox was always selecting the first option rather than the "selected" option
- switched the `filters` array from an EmberArray instance over to a tracked built in Array instance and changed the "edit" behaviour when changing a filter type so we fully replace a `Filter` instance in the filters array with a new instance which causes an overall re-render of that filter row avoiding the Firefox issue

TryGhost/Ghost-Admin,TryGhost/Ghost-Admin