[TOASTR] ViewDestroyedError: Attempt to use a destroyed view: detectChanges

### Issue type

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

* [x] bug report
* [ ] feature request

### Issue description

**Current behavior:**

When using the toastr, the first click of a button triggering the toastr works fine, however the second, and subsequent clicks generate a ViewDestroyedError. The Toastr itself still renders but the following error also displays in the console:

button.component.html:4 ERROR Error: ViewDestroyedError: Attempt to use a destroyed view: detectChanges
at viewDestroyedError (core.js:19641)
at Object.debugUpdateDirectives [as updateDirectives] (core.js:30040)
at checkAndUpdateView (core.js:29439)
at callWithDebugContext (core.js:30309)
at Object.debugCheckAndUpdateView [as checkAndUpdateView] (core.js:30011)
at ViewRef_.push../node_modules/@angular/core/fesm5/core.js.ViewRef_.detectChanges (core.js:20686)
at patch (index.js:1874)
at NbToastContainer.push../node_modules/@nebular/theme/fesm5/index.js.NbToastContainer.updateContainer (index.js:19154)
at NbToastContainer.push../node_modules/@nebular/theme/fesm5/index.js.NbToastContainer.destroy (index.js:19102)
at index.js:19147

**Expected behavior:**

The toastr should be able to be clicked multiple times and destroy correctly without the error.

**Steps to reproduce:**

Set up a button trigger that on click calls the simple showToast function from the documentation. Look in the devTools on chrome and the error should show up.

**Related code:**

```
insert short code snippets here
```
My code is set up like this:
Component.ts
` showToast() {
this.index ++;
const duration = 2000;
let status = this.toaststatus;
let position = this.position;
this.toastrService.show(
this.message,
this.title || 'Title',
{ position, status, duration });
}`

html
`{{label}}`

### Other information:

**npm, node, OS, Browser**
```

```

**Angular, Nebular**
```
Nebular version: '4.6.0', Angular version: 8.2
```