the internal telephone input can not show

### Issue type
UI
**I'm submitting a ...** (check one with "x")

* [x] bug report
* [x] feature request
* [ ] question about the decisions made in the repository

### Issue description
I used the NgxIntlTelInput to add an internal telephone input by the link: the https://www.npmjs.com/package/ngx-intl-tel-input but the UI showed incorrectly. The national dropdown was broken.


**Current behavior:**

**Expected behavior:**

**Steps to reproduce:**

**Related code:**

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### Other information:

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