nix: fix nix develop .#python-scripts (#19218)

Without this I get:

> * Getting build dependencies for wheel...
> * Building wheel...
> Successfully built gguf-0.17.1-py3-none-any.whl
> Finished creating a wheel...
> Finished executing pypaBuildPhase
> Running phase: pythonRuntimeDepsCheckHook
> Executing pythonRuntimeDepsCheck
> Checking runtime dependencies for gguf-0.17.1-py3-none-any.whl
>   - requests not installed
For full logs, run:
    nix log /nix/store/x0c4a251l68bvdgang9d8v2fsmqay8a4-python3.12-gguf-0.0.0.drv

I changed a bit the style to make it more terse ~> more elegant in my
opinion.

.devops/nix/package-gguf-py.nix

@@ -3,6 +3,7 @@
   llamaVersion,
   numpy,
   tqdm,
+  requests,
   sentencepiece,
   pyyaml,
   poetry-core,
@@ -20,6 +21,7 @@ buildPythonPackage {
     tqdm
     sentencepiece
     pyyaml
+    requests
   ];
   src = lib.cleanSource ../../gguf-py;
   pythonImportsCheck = [