feat(modules/NativeBridgeModule): map Unit return to null

app/src/main/kotlin/io/github/revenge/xposed/modules/NativeBridgeModule.kt

@@ -7,6 +7,8 @@ import java.lang.reflect.Method
 /**
  * See for possible return types:
  * https://github.com/facebook/react-native/blob/c23e84ae9/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/bridge/Arguments.kt#L19
+ *
+ * You may return a [Unit] and the resulting value will be `null`.
  */
 typealias BridgeMethodCallback = (args: BridgeMethodArgs) -> Any?
 
@@ -47,9 +49,11 @@ class NativeBridgeModule : Module() {
         }
     }
 
-
     private fun Any?.toNativeObject(): Any? =
-        argumentsMakeNativeObject.invoke(null, this)
+        argumentsMakeNativeObject.invoke(null, when (this) {
+            Unit -> null
+            else -> this
+        })
 
     override fun onInit(packageParam: XC_LoadPackage.LoadPackageParam) = with(packageParam) {
         this@NativeBridgeModule.packageParam = packageParam