Select the menu width automatically

A follow-up to https://phabricator.wikimedia.org/T76196 .
an early return by checking this.options.menuWidth will simplify the code below
```javascript
if (  this.options.menuWidth ) {
      return  this.options.menuWidth
}
```

Or even 
```javascript
columns: columnsOptions[ this.options.menuWidth || this.getMenuWidth() ],
```