[FIX] survey : fix datetimepicker initialization - BS4

Since BS4, input-group is used instead of form-controll.
The initialisation was not correctly made because it didn't find
the datetimepicker.
There were several resulting issues:
- Max and Min date were not taken into account
- Clicking on the text area of date field was not opening the
    datetimepicker as config was not defined (allowInputToggle option)

Task ID : 1911291
Closes PR #28966

addons/survey/static/src/js/survey.js

@@ -183,7 +183,7 @@ if(!the_form.length) {
     // frontend does not load moment locale at all.
     // so wait until DOM ready with locale then init datetimepicker
     ready_with_locale.then(function(){
-        $('.form-control.date').datetimepicker({
+        $('.input-group.date').datetimepicker({
             format : time.getLangDateFormat(),
             minDate: moment({ y: 1900 }),
             maxDate: moment().add(200, "y"),