[Feature]: Allow null for Select, Combobox, ToggleGroup, etc.

[kilobyte2007]

Describe the feature

Hi, I have already raised this in #880 but I see it's closed as fixed, but it was only fixed inside the nullish check and the type was not adjusted accordingly.

In v2 (1 alpha) I see that AcceptableValue is used everywhere alongside | undefined for modelValue, but in a lot of cases allowing a null alongside undefined makes sense as we often can have a null value come from a database and or an endpoint.

Additional information

• I intend to submit a PR for this feature.
• I have already implemented and/or tested this feature.

[zernonia]

Thanks for bringing this up again @kilobyte2007 ! The previous fix was to accept null for rendering the placeholder. We will handle this change in v2 as we want to make it consistent with other form components 😁