Incorrect date

### Issue type

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

* [X] bug report
* [ ] feature request

### Issue description

**Current behavior:**

Change the format of date to HH:MM
The Date should be the same of PC

**Expected behavior:**

The date is incorrect

**Steps to reproduce:**

Add this option in the chat configuration --> dateFormat="HH:MM"

**Related code:**

```
insert short code snippets here
```

### Other information:

**npm, node, OS, Browser**
```
Browser: Chrome
Angular 9.2.3
Windows 10

```

**Angular, Nebular**
"@nebular/eva-icons": "5.1.0",
"@nebular/theme": "^5.1.0",

```