Use Intent.createChooser() instead of directly calling startActivity() with the Intent

[cketti]

Calling startActivity() on the intent will only show a chooser dialog when there's more than one app capable of receiving the intent. Then the user will also be able to select one of these apps as default app. When sharing content this is usually not the desired behavior.

Using [Intent.createChooser()](https://developer.android.com/reference/android/content/Intent.html#createChooser%28android.content.Intent, java.lang.CharSequence%29) will always display a chooser dialog and not allow the user to select a default application.