* Properly translate errors in AddThreepid.ts
Part of https://github.com/vector-im/element-web/issues/9597
* Use translated message
* Avoid returning undefined ever
* More usage
* Introduce UserFriendlyError
* Use UserFriendlyError
* Add more usage instead of normal error
* Use types and translatedMessage
* Fix lints
* Update i18n although it's wrong
* Use unknown for easier creation from try/catch
* Use types
* Use error types
* Use types
* Update i18n strings
* Remove generic re-label of HTTPError
See https://github.com/matrix-org/matrix-react-sdk/pull/10432#discussion_r1156468143
The HTTPError already has a good label and it isn't even translated if we re-label it here in this way generically
Probably best to just remove in favor of thinking about a translations in general from the `matrix-js-sdk`, see https://github.com/matrix-org/matrix-js-sdk/issues/1309
* Make error message extraction generic
* Update i18n strings
* Add tests for email addresses
* More consistent error logging to actually see error in logs
* Consistent error handling
* Any is okay because we have a fallback
* Check error type
* Use dedicated mockResolvedValue function
See https://github.com/matrix-org/matrix-react-sdk/pull/10432#discussion_r1163344034
