refactor: replace empty slice literal with `var`
An empty slice can be represented by `nil` or an empty slice literal. They are
functionally equivalent — their `len` and `cap` are both zero — but the `nil`
slice is the preferred style. For more information about empty slices,
see [Declaring Empty Slices](https://github.com/golang/go/wiki/CodeReviewComments#declaring-empty-slices).
Co-authored-by: deepsource-autofix[bot] <62050782+deepsource-autofix[bot]@users.noreply.github.com>
