efl_ui_text: clear selection after cut

Test Plan:
```
#define EFL_EO_API_SUPPORT 1
#define EFL_BETA_API_SUPPORT 1

#include <Eina.h>
#include <Elementary.h>
#include <Efl_Ui.h>

static void
_gui_quit_cb(void *data EINA_UNUSED, const Efl_Event *event EINA_UNUSED)
{
   efl_exit(0);
}

static void
_gui_setup()
{
   Eo *win, *box;

   win = efl_add(EFL_UI_WIN_CLASS, efl_main_loop_get(),
                 efl_ui_win_type_set(efl_added, EFL_UI_WIN_TYPE_BASIC),
                 efl_text_set(efl_added, "Hello World"),
                 efl_ui_win_autodel_set(efl_added, EINA_TRUE));

   // when the user clicks "close" on a window there is a request to delete
   efl_event_callback_add(win, EFL_UI_WIN_EVENT_DELETE_REQUEST, _gui_quit_cb, NULL);

   box = efl_add(EFL_UI_BOX_CLASS, win,
                efl_content_set(win, efl_added),
                efl_gfx_hint_size_min_set(efl_added, EINA_SIZE2D(360, 240)));

   efl_add(EFL_UI_TEXT_CLASS, box,
           efl_text_markup_set(efl_added, "Hello World.<ps>This is an <b>Efl.Ui</b> application!"),
           efl_text_interactive_selection_allowed_set(efl_added, EINA_TRUE),
           efl_text_multiline_set(efl_added,EINA_TRUE),
           efl_gfx_hint_weight_set(efl_added, 1.0, 0.9),
           efl_gfx_hint_align_set(efl_added, 0.5, 0.5),
           efl_pack(box, efl_added));

   efl_add(EFL_UI_BUTTON_CLASS, box,
           efl_text_set(efl_added, "Quit"),
           efl_gfx_hint_weight_set(efl_added, 1.0, 0.1),
           efl_pack(box, efl_added),
           efl_event_callback_add(efl_added, EFL_UI_EVENT_CLICKED,
                                  _gui_quit_cb, efl_added));
}

EAPI_MAIN void
efl_main(void *data EINA_UNUSED, const Efl_Event *ev EINA_UNUSED)
{
   _gui_setup();
}
EFL_MAIN()
```

Reviewers: woohyun, bowonryu, segfaultxavi

Reviewed By: segfaultxavi

Subscribers: segfaultxavi, cedric, #reviewers, #committers

Tags: #efl

Differential Revision: https://phab.enlightenment.org/D8833

src/lib/elementary/efl_ui_text.c

@@ -1231,6 +1231,7 @@ _cut_cb(Eo *obj)
    _selection_store(EFL_UI_SELECTION_TYPE_CLIPBOARD, obj);
    efl_text_interactive_selection_cursors_get(obj, &start, &end);
    efl_canvas_text_range_delete(obj, start, end);
+   _efl_ui_text_select_none(obj, sd);
 }
 
 static void