KeyUp and KeyDown events do not enable scrolling on autocomplete

### Issue type

**I'm submitting a ...** (check one with "x")

* [X] feature request

### Issue description

**Current behavior:**
When creating an autocomplete, if you keyup and keydown on it, the events do not scroll the autocomplete

**Expected behavior:**
When using the up and down arrow keys on the keyboard, the autocomplete should be scrolled

**Steps to reproduce:**
select autocomplete, press up or down on keyboard until focus disappears

**Related code:**
[StackBlitz](https://stackblitz.com/edit/github-stjwwr)

### Other information:

**npm, node, OS, Browser**
```
Node: 12.14.0
Npm: 6.14.8
OS: Windows (10)
Browser: Chrome
```

**Angular, Nebular**
```
Angular: 11.2.14
Nebular: 7
```