Can not set icon pack for route-tabset - route-tabset.component.ts line 105

### Issue type

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

* [ X] bug report
* [ ] feature request

### Issue description

**Current behavior:**

Can not set icon pack for route-tabset
**Expected behavior:**

be able to set icon pack for route-tabset
**Steps to reproduce:**

public tabs = [
{
title: 'Campaigns',
route: '/pages/admin/campaigns',
icon: { icon: 'bullhorn', pack: 'fa' },
responsive: true, // hide title before `route-tabs-icon-only-max-width` value
},
....

**Related code:**

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### Other information:

**npm, node, OS, Browser**
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**Angular, Nebular**
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