500 crash when creating Rack Reservation with invalid units

[jathanism]

Environment

• Python version: all
• Nautobot version: 1.0.0b1-b3
• I tested both locally and on demo.nautobot.com

Steps to Reproduce

1. Have a Rack (e.g. rack1)
2. Navigate to *Organization > Racks > Reservations > [+]
3. Populate rack1 as your rack, then invalid value in the Unit field, such as pizza

Expected Behavior

Expecting a 400 error that is captured by the UI and emits invalid value error message for that field

Observed Behavior

Traceback

Internal Server Error: /dcim/rack-reservations/4d2a3872-6b5a-4dcd-bff7-c527fff96d79/edit/
Traceback (most recent call last):
  File "/Users/jathan/Library/Caches/pypoetry/virtualenvs/nautobot-b2ttWva6-py3.8/lib/python3.8/site-packages/django/core/handlers/exception.py", line 47, in inner
    response = get_response(request)
  File "/Users/jathan/Library/Caches/pypoetry/virtualenvs/nautobot-b2ttWva6-py3.8/lib/python3.8/site-packages/django/core/handlers/base.py", line 181, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/Users/jathan/Library/Caches/pypoetry/virtualenvs/nautobot-b2ttWva6-py3.8/lib/python3.8/site-packages/sentry_sdk/integrations/django/views.py", line 67, in sentry_wrapped_callback
    return callback(request, *args, **kwargs)
  File "/Users/jathan/Library/Caches/pypoetry/virtualenvs/nautobot-b2ttWva6-py3.8/lib/python3.8/site-packages/django/views/generic/base.py", line 70, in view
    return self.dispatch(request, *args, **kwargs)
  File "/Users/jathan/sandbox/src/nautobot/nautobot/core/views/generic.py", line 266, in dispatch
    return super().dispatch(request, *args, **kwargs)
  File "/Users/jathan/sandbox/src/nautobot/nautobot/utilities/views.py", line 94, in dispatch
    return super().dispatch(request, *args, **kwargs)
  File "/Users/jathan/Library/Caches/pypoetry/virtualenvs/nautobot-b2ttWva6-py3.8/lib/python3.8/site-packages/django/views/generic/base.py", line 98, in dispatch
    return handler(request, *args, **kwargs)
  File "/Users/jathan/sandbox/src/nautobot/nautobot/core/views/generic.py", line 293, in post
    if form.is_valid():
  File "/Users/jathan/Library/Caches/pypoetry/virtualenvs/nautobot-b2ttWva6-py3.8/lib/python3.8/site-packages/django/forms/forms.py", line 177, in is_valid
    return self.is_bound and not self.errors
  File "/Users/jathan/Library/Caches/pypoetry/virtualenvs/nautobot-b2ttWva6-py3.8/lib/python3.8/site-packages/django/forms/forms.py", line 172, in errors
    self.full_clean()
  File "/Users/jathan/Library/Caches/pypoetry/virtualenvs/nautobot-b2ttWva6-py3.8/lib/python3.8/site-packages/django/forms/forms.py", line 374, in full_clean
    self._clean_fields()
  File "/Users/jathan/Library/Caches/pypoetry/virtualenvs/nautobot-b2ttWva6-py3.8/lib/python3.8/site-packages/django/forms/forms.py", line 392, in _clean_fields
    value = field.clean(value)
  File "/Users/jathan/Library/Caches/pypoetry/virtualenvs/nautobot-b2ttWva6-py3.8/lib/python3.8/site-packages/django/contrib/postgres/forms/array.py", line 31, in clean
    value = super().clean(value)
  File "/Users/jathan/Library/Caches/pypoetry/virtualenvs/nautobot-b2ttWva6-py3.8/lib/python3.8/site-packages/django/forms/fields.py", line 149, in clean
    value = self.to_python(value)
  File "/Users/jathan/sandbox/src/nautobot/nautobot/utilities/forms/widgets.py", line 124, in to_python
    value = ",".join([str(n) for n in parse_numeric_range(value)])
  File "/Users/jathan/sandbox/src/nautobot/nautobot/utilities/forms/utils.py", line 33, in parse_numeric_range
    begin, end = int(begin.strip(), base=base), int(end.strip(), base=base) + 1
ValueError: invalid literal for int() with base 10: 'pizza'