elementary_tizen/ctxpopup: rename widget_event to input_event_handler

elementary_tizen/ctxpopup: rename widget_event to input_event_handler

`widget_event` has been renamed to `input_event_handler` since commit
298d112dbb1151fe119480af275931b45828fafd.

For tizen elc_ctxpopup, KeyEvent will work again.

Also, Fixes compiler warnings.
```
 ../src/lib/elementary_tizen/elc_ctxpopup.c:1314:1: warning: '_elm_ctxpopup_efl_ui_widget_event' defined but not used [-Wunused-function]
  1314 | _elm_ctxpopup_efl_ui_widget_event(Eo *obj, Elm_Ctxpopup_Data *sd, Evas_Object *src EINA_UNUSED, Evas_Callback_Type type, void *event_info)
       | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 ../src/lib/elementary_tizen/elc_ctxpopup.c:165:1: warning: '_key_action_move' defined but not used [-Wunused-function]
   165 | _key_action_move(Evas_Object *obj, const char *params)
```

@tizen_fix

Change-Id: I95faa5d0d5647df276be03de109e45c2baaf6bfe