Fix a crash (Android) - CustomKeyboardLayout -> clearKeyboardOverlayMode -> NullPointer (#869)

Author: M-i-k-e-l

lib/android/src/main/java/com/wix/reactnativeuilib/keyboardinput/CustomKeyboardLayout.java

@@ -2,6 +2,7 @@
 
 import android.content.Context;
 import android.view.View;
+import android.view.Window;
 import android.view.WindowManager;
 import android.view.inputmethod.InputMethodManager;
 import android.widget.EditText;
@@ -166,11 +167,17 @@ private int getHeightForCustomContent() {
     }
 
     private void setKeyboardOverlayMode() {
-        getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_PAN);
+        Window window = getWindow();
+        if (window != null) {
+            window.setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_PAN);
+        }
     }
 
     private void clearKeyboardOverlayMode() {
-        getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_RESIZE);
+        Window window = getWindow();
+        if (window != null) {
+            window.setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_RESIZE);
+        }
     }
 
     private void sendCustomKeyboardResignedEvent() {