VoiceSpeech get English announcement when I set chinese language

Nobody has claimed this yet.

I use this example to test(https://github.com/mapbox/mapbox-navigation-android/blob/main/examples/src/main/java/com/mapbox/navigation/examples/core/MapboxVoiceActivity.kt)

I set the language to SIMPLIFIED_CHINESE.
When the network is connected, the speechCallback get chinese announcement.
But I turn off the network, speechCallback get English announcement.

```
private val speechApi: MapboxSpeechApi by lazy {
MapboxSpeechApi(this, getMapboxAccessTokenFromResources(), Locale.SIMPLIFIED_CHINESE.language)
}

private val voiceInstructionsPlayer: MapboxVoiceInstructionsPlayer by lazy {
MapboxVoiceInstructionsPlayer(
this,
getMapboxAccessTokenFromResources(),
Locale.SIMPLIFIED_CHINESE.language
)
}

val routeOptions: RouteOptions = RouteOptions.builder()
.applyDefaultNavigationOptions()
.applyLanguageAndVoiceUnitOptions(this)
.language(Locale.getDefault().language)
.coordinatesList(listOf(origin, destination))
.voiceInstructions(true)
.build()

private val speechCallback =
MapboxNavigationConsumer> { expected ->
expected.fold(
{ error ->
// The data obtained in the form of an error is played using
// voiceInstructionsPlayer.
voiceInstructionsPlayer.play(
error.fallback,
voiceInstructionsPlayerCallback
)
},
{ value ->
// The data obtained in the form of speech announcement is played using
// voiceInstructionsPlayer.
voiceInstructionsPlayer.play(
value.announcement,
voiceInstructionsPlayerCallback
)
}
)
}
```
**Mapbox Navigation SDK version:mapbox-navigation-android-2.0.0-rc.1**

Start with examples/src/main/java/com/mapbox/navigation/examples/core/MapboxVoiceActivity.kt and trace speechCallback when the network is unavailable. Compare the configured SIMPLIFIED_CHINESE language with the fallback passed to voiceInstructionsPlayer.play. Done means offline speech announcements remain Chinese rather than switching to English.

Written by the indexing model from the issue text.