Ensure the PageParameterDataProviderType query validation support arrays of integers.

Setup

1. Create a form, with a record selector inside it.
2. Add a list rows data source, assign it to the record selector.
3. Add a querystring parameter to the page (e.g. userIds) and set its type to numeric.
4. Set the record selector's default value to this userIds parameter, and check "allow multiple".

The issue

• In editing: if you set ?userIds=1,2,3, the record selector will choose those record IDs.
• In preview/public: PageParameterDataProviderType.init chooses a validator, based on the page parameter type, which in this case is ensurePositiveInteger. However, 1,2,3 isn't a valid number, so we throw an error: "Value '2,3' is not a valid integer or convertible to an integer."