Smart table dependency ng2-completer 2.0.8 imports HttpClientModule

### Issue type

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

* [X] bug report
* [ ] feature request

### Issue description

**Current behavior:**

Interceptors doesn't catch httpClient calls from lazy modules.

**Expected behavior:**

Interceptor should catch any httpClient call.

**Steps to reproduce:**

nebular 3.1.0, ng2-smart-table 1.3.5 and ng2-completer 2.0.8

**Related code:**

```
insert short code snippets here
```

### Other information:

**npm, node, OS, Browser**
```
npm: 10.15.0
OS: Ubuntu 18
Browser: Chrome
```

**Angular, Nebular**
```
angular: 7.2.0
nebular: 3.1.0
```

There is a known problem with HttpClientModule, it can't be imported multiple times. So, no other package should import it (was removed from nebular too https://github.com/akveo/nebular/issues/631).

But, not long ago, smart table started to use ng2-completer 2.0.8 but this library calls HttpClientModule to work and overrides the HttpClient calls. And some of our calls weren't catched by the interceptors.

This was acknowledged to ng2-completer community so they removed it in version 3.0.0-beta.2 (https://github.com/oferh/ng2-completer/issues/393). And now everything works fine.

**Should version 3.0.0-beta.2 be mandatory in the package.json? (this solves the problem)**

Thanks in advance.