fix: Fix takeSnapshot not working on Android (#961)

Accessing previewView.bitmap was throwing an error because it wasn't being done on the main thread.
Any access to previewView needs to be done on the main (UI) thread. This commit fixes the issue by
ensuring this access is now run on the main thread.

Fixes #547

android/src/main/java/com/mrousavy/camera/CameraView+TakeSnapshot.kt

@@ -22,7 +22,9 @@ suspend fun CameraView.takeSnapshot(options: ReadableMap): WritableMap = corouti
       camera.cameraControl.enableTorch(true).await()
     }
 
-    val bitmap = this@takeSnapshot.previewView.bitmap ?: throw CameraNotReadyError()
+    val bitmap = withContext(coroutineScope.coroutineContext) {
+      previewView.bitmap ?: throw CameraNotReadyError()
+    }
 
     val quality = if (options.hasKey("quality")) options.getInt("quality") else 100