fix android can't input unicode characters

fix hide soft keyboard by press 'back' button,
 then click current focus text edit/line edit control,
 soft keyboard won't show again

add features:
  press enter key with line edit control will hide soft keyboard

scene/gui/text_edit.cpp

@@ -857,6 +857,8 @@ void TextEdit::_input_event(const InputEvent& p_input_event) {
 			} else {
 
 				selection.selecting_mode=Selection::MODE_NONE;
+                // notify to show soft keyboard
+                notification(NOTIFICATION_FOCUS_ENTER);
 			}
 
 		} break;