nl-BE (Flemish, Dutch Belgian) misrepresented as Dutch-Belarusian

*I'm submitting a ...*
- [x] bug report

## General infomration
We have the problem that Netflix has streams for children movies in our native Dutch language, but it is never selected correctly. It is wrongly translated into Dutch-Belarusian, but also not considered Dutch.

### Prerequisites

* [x] Are you running the latest version?

### Description
Apart from not selecting native Dutch(nl-BE), it is defaulting to German (ger).

**Expected behavior:** [What you expected to happen]
Actually what we would like to have (for children movies):
- nl-BE
- nl
- en (with nl subtitles)
- native language (with nl subtitles)

**Actual behavior:** [What actually happened]
Usually it defaults to German (ger) for audio and subtitles

### Installation
* [x] I installed the plugin via zip from the Releases page
* [ ] I´m using the Netflix Repo
* [ ] I´m using a different source (Please tell which)

### Operating System
* [ ] Linux (x86/x64)
* [ ] OSX (x86/x64)
* [ ] Windows (x86/x64)
* [x] Linux (ARM)
* [ ] Android

#### Additional informatin on the environment
We are using LibreELEC v8.95.003 using Kodi v18.0-RC5 and plugin.video.netflix v0.13.21.

Reproduce the language-selection behavior in plugin.video.netflix on the reported LibreELEC/Kodi environment, then trace how nl-BE and fallback languages are interpreted. Done means nl-BE is recognized as Belgian Dutch rather than Dutch-Belarusian, with the requested Dutch and subtitle fallback order working correctly.

Written by the indexing model from the issue text.