nb-tag-list not working

**Issue type**

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

* [x] bug report
* [ ] feature request

### Issue description

**Current behavior:**

I used the code given on [https://akveo.github.io/nebular/docs/components/tag/overview#nbtaglistcomponent](url) in my home.component.ts
It gives me error as shown below :

Now, when I declared NbTagListComponent in HomeModule, It gives me error as shown below :

**Expected behavior:**

It should work as showed on nebular site [https://akveo.github.io/nebular/docs/components/tag/overview#nbtaglistcomponent](url)

**Steps to reproduce:**
1. Use the template and .ts code in your component.
2. Add required methods and imports.
3. Initialise 'trees' array with some static values.
4. Compile

**Related code:**
HomeModule.ts

```
import { ReactiveFormsModule } from '@angular/forms';
import { FormsModule } from './../forms/forms.module';
import { NbCardModule,
NbButtonModule, NbTagModule,
NbInputModule, NbFormFieldModule, NbAutocompleteModule, NbIconModule, NbTagListComponent } from '@nebular/theme';
import { UtilityService } from './../../@core/utils/utility.service';
import { NgModule } from '@angular/core';
import { CommonModule } from '@angular/common';

import { HomeRoutingModule } from './home-routing.module';

@NgModule({
declarations: [NbTagListComponent],
imports: [
HomeRoutingModule,
CommonModule,
FormsModule,
ReactiveFormsModule,
NbCardModule,
NbButtonModule,
NbTagModule,
NbInputModule,
NbFormFieldModule,
NbAutocompleteModule,
NbIconModule,
],
providers: [UtilityService],
})
export class HomeModule { }

```

### Other information:

**npm, node, OS, Browser**
```
Angular CLI: 12.1.0
Node: 12.14.1
npm: 6.13.4
OS: darwin x64
Browser: Chrome
```

**Angular, Nebular**
```
Nebular : 8.0.0
```