nix1: fix `perl-bindings` build

Nix 1.11 builds perl-bindings by default, `nix1.perl-bindings` fails
with the following error:

```
building
no Makefile, doing nothing
installing
install flags: install
make: *** No rule to make target 'install'.  Stop.
```

This is probably due to #47316. Previously the `perl-bindings` were
referenced to `nix1` instead of the `perl-bindings` function as Nix 1.11
built those during its build process.