python3Packages.openllm-core: fix optional-dependencies evaluation

Without the change eval fails as:

    $ nix build --no-link -f. python3Packages.openllm-core.optional-dependencies
    error:
           79|   passthru.optional-dependencies =
             |   ^
           80|   let

       error: attribute 'accelerate' missing

From what I see `accelerate` was always missing in `transflrmers` package.
While at it fixed `full` evaluation by disambiguating between input
argument and `passthru` attribute.

pkgs/development/python-modules/openllm-core/default.nix

@@ -70,9 +70,12 @@ buildPythonPackage rec {
       transformers
       # trl
     ] ++ transformers.optional-dependencies.torch
-      ++ transformers.optional-dependencies.tokenizers
-      ++ transformers.optional-dependencies.accelerate;
-    full = with passthru.optional-dependencies; ( vllm ++ bentoml ++ fine-tune );
+      ++ transformers.optional-dependencies.tokenizers;
+    full = with passthru.optional-dependencies; (
+      vllm
+      # use absolute path to disambiguate with derivbation argument
+      ++ passthru.optional-dependencies.bentoml
+      ++ fine-tune );
   };
 
   # there is no tests