Adding a badge to nb-action on header doesnt render.

### Issue type

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

* [X ] bug report
* [ ] feature request

### Issue description
Add a nb-badge to a nb-action inside a header, renders the nb-action without the badge.

**Current behavior:**
I have a header, then import NbBadgeModule in the header module, next declare the nb-badge inside a nb-action, it renders the action without the badge.

**Expected behavior:**
The badge renders ok inside a nb-action icon. (or next to)

**Related code:**

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### Other information:

**npm, node, OS, Browser**
Node: v14.3.0
OS: Arco Linux B
Browser: Google Chrome 83

**Angular, Nebular**
Angular: 8.0.3
Nebular: 4.6.0