After setting MapStyle from `.standard(lightPreset: .night)` to `.standard` it remains in night style

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## Environment

- Xcode version: Version 16.4 (16F6)
- iOS version: iOS 26.0 (23A343)
- Devices affected: iPhone
- Maps SDK Version: 11.15.1

## Observed behavior and steps to reproduce

After setting MapStyle from `.standard(lightPreset: .night)` to `.standard` it remains in night style

```swift
...
init()
mapView.mapboxMap.mapStyle = .standard
}

override func traitCollectionDidChange(_ previousTraitCollection: UITraitCollection?) {
super.traitCollectionDidChange(previousTraitCollection)

if previousTraitCollection?.hasDifferentColorAppearance(comparedTo: traitCollection) == true {
if traitCollection.userInterfaceStyle == .dark {
mapView.mapboxMap.mapStyle = .standard(lightPreset: .night)
} else {
mapView.mapboxMap.mapStyle = .standard
}
}
}
```

## Expected behavior

Map style is set to same "standard" as it was in init.

## Notes / preliminary analysis

This behaviour seems to stem from fact that in `.standard` lightPreset is nil which later causes it to be ignored in `MapStyleReconciler` as value to be changed.
https://github.com/mapbox/mapbox-maps-ios/blob/0c92cef511d5b17d1eced72e78308c68fc01675b/Sources/MapboxMaps/ContentBuilders/MapContent/MapStyleReconciler.swift#L119

Is this actually expected behaviour from `.standard` use? Or is it a bug?

Start with Sources/MapboxMaps/ContentBuilders/MapContent/MapStyleReconciler.swift around line 119 and reproduce the transition from .standard(lightPreset: .night) to .standard using the issue's iOS example. Trace how a nil lightPreset is handled; done means the map returns to the standard style after the trait changes.

Written by the indexing model from the issue text.