Private fields don't work with initializers

[nielsenko]

@RealmModel()
class _WithPrivateFields {
  int _withDefault = 0;
}

will generate a constructor signature like:

  WithPrivateFields({
    int _withDefault = 0,
  })

which is not legal dart, as named parameters cannot be prefixed with _

[sync-by-unito]

➤ PM Bot commented:

Jira ticket: RDART-1010