Widget UI wrapper remains when effectively empty

**To Reproduce**
Steps to reproduce the behavior:
- Add an `apostrophe-rich-text` singleton to a page, with a `controls` option with `movable: false` and `removable: false`. Add the singleton on the live page and hover over.

```
{{ apos.singleton(data.page, 'text', 'apostrophe-rich-text', {
controls: {
movable: false,
removable: false
}
}) }}
```

**Expected behavior**
Since there are no controls, there should be no visible controls UI.

**Describe the bug**
A small, empty controls wrapper still appears on hover. This contains a hidden `clone-item` button.

**Server Operating System**
The server (which might be your dev laptop) on which Apostrophe is running. Linux? MacOS X? Windows? Is Docker involved?

Reproduce the issue with an apostrophe-rich-text singleton whose controls set movable and removable to false, then inspect the hover-rendered controls wrapper and its hidden clone-item button. Done means the live page shows no visible controls UI when no controls are available.

Written by the indexing model from the issue text.