Missing Assets for Widgets Used in Formsets

[blasferna]

There's an issue with the package where the necessary CSS and JavaScript dependencies for widgets are not loaded when these widgets are placed in a formset within a form. Please note that this issue does not occur when the same widget is added directly to the main form.

Steps to Reproduce:

The issue is reproducible using the django-bootstrap-datepicker-plus package with the following steps:

1. Install the package: pip install django-bootstrap-datepicker-plus

2. Add it to INSTALLED_APPS:

   INSTALLED_APPS = [
       "bootstrap_datepicker_plus",
   ]

3. Create a custom widget without redefining the CSS and JavaScript:

   from bootstrap_datepicker_plus.widgets import (
       DatePickerInput,
       TimePickerInput
   )
   
   class DatePickerWidget(DatePickerInput):
       def __init__(self, attrs=None, format=None):
           attrs = attrs or {}
           attrs.update({'class': 'datepicker'})
           super(DatePickerWidget, self).__init__(attrs, format)

4. Assign the custom widget to a formset example (in this case, PaymentTermForm):

   from demo.widgets import DatePickerWidget
   
   class PaymentTermForm(forms.ModelForm):
       def __init__(self, *args, **kwargs):
           ...
       class Meta:
           model = PaymentTerm
           fields = "__all__"
           widgets = {"due_date": DatePickerWidget}