fix: guard against null in StreetView panorama change listeners

[balazsbarany]

Description

The OnStreetViewPanoramaChangeListener and OnStreetViewPanoramaCameraChangeListener Java interfaces in play-services-maps do not annotate their callback parameters as @NonNull. The GMS dynamite module (policy_maps_core_dynamite) can deliver null to these listeners on certain devices and Play Services versions.

In StreetViewPanoramaPropertiesNode.onAttached(), both lambdas assigned the callback value directly to non-nullable Kotlin state fields (rawLocation and rawPanoramaCamera). The Kotlin compiler inserts an implicit null-check intrinsic at lambda entry — before the assignment — which throws a NullPointerException when null arrives, crashing the app.

Crash trace

Fatal Exception: com.google.maps.api.android.lib6.common.apiexception.f: NullPointerException:
  Attempt to invoke virtual method 'java.lang.Class java.lang.Object.getClass()' on a null object reference
    at com.google.maps.android.compose.streetview.StreetViewPanoramaPropertiesNode.onAttached$lambda$3

Lambda index 3 in onAttached() is the setOnStreetViewPanoramaChangeListener callback. The getClass() call is the Kotlin-generated null check, not application code.

Changes

Guard both listener assignments with a null-safe let block in StreetViewPanoramaUpdater.kt:

// before
panorama.setOnStreetViewPanoramaChangeListener {
    cameraPositionState.rawLocation = it
}

// after
panorama.setOnStreetViewPanoramaChangeListener {
    it?.let { cameraPositionState.rawLocation = it }
}

The same pattern is applied to setOnStreetViewPanoramaCameraChangeListener for consistency, as StreetViewPanoramaCamera is also non-nullable in rawPanoramaCamera but the Java interface carries no @NonNull guarantee.

Testing

The fix is purely defensive against a null delivery from the GMS layer, which cannot be injected in an instrumented test. The existing StreetViewTests continue to exercise the normal flow unchanged.

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