Inconsistent names in language dropdown

### Description of the bug

Language selector shows "Norsk bokmål" and "Nynorsk". This is inconsistent - should be either "Bokmål" and "Nynorsk", or "Norsk bokmål" and "Norsk nynorsk".

### Steps To Reproduce

Include language selector in app, see inconsistent language names.

### Additional Information


The way it's done in the Altinn Inbox (which we should be consistent with):


### Acceptance criteria
- [ ] Given that the language selector is added to a form layout, when the dropdown is selected and if "Bokmål" or "Nynorsk" is a supported language, then it should be shown with the values "Bokmål" and/or "Nynorsk" ie. the same way it's shown in the Altinn Inbox
- [ ] Given that other languages are supporte, when the dropdown is selected, those other languages should be shown in their own language ie. English, Deutsch etc.