`filterWhereIn()` / `filterWhereNotIn()` still fails with boolean values after #13266

[o1y]

Bug description

The fix in #13266 for array_flip() only handles null values via ??, but booleans like false still cause the error:

array_flip(): Can only flip string and integer values, entry skipped
  at vendor/statamic/cms/src/Stache/Query/Builder.php:160

I’m still using v5 in many installations, and unfortunately some queries are broken because of this 🤒

How to reproduce

In tinker, simply run for a toggle field:

\Statamic\Facades\Entry::query()->whereIn('any_toggle_field', [false, null])->get();

Logs

Environment

5.73.6

Installation

Fresh statamic/statamic site via CLI

Additional details

possible workaround

->where(function ($q) {
    $q->where('my_field', false)
        ->orWhereNull('my_field');
})