Fix keyboard change detection: separate StatefulKeyboardResizeableFragment and KeyboardResizeableFragment, add ability to handle keyboard detection inside nested fragments

Keyboard detector refactor

@@ -253,3 +258,4 @@
+                ?: throw ShouldNotHappenException("viewControllerClass is null")
     }
 
     override fun toString(): String = "${super.toString()} ViewController: $viewControllerClass"