python3Packages: provide setuptools-scm with toml[i] by default and remove duplicated toml packages

Some packages seem to still require toml despite setuptools-scm having switched to tomli.
If it is missing the version number in dist.into is set to 0.0.0 and silently all version pins break.

pkgs/development/python-modules/asttokens/default.nix

@@ -1,5 +1,5 @@
 { lib, fetchPypi, fetchpatch, buildPythonPackage,
-  setuptools-scm, toml, six, astroid, pytest
+  setuptools-scm, six, astroid, pytest
 }:
 
 buildPythonPackage rec {
@@ -21,7 +21,7 @@ buildPythonPackage rec {
     })
   ];
 
-  propagatedBuildInputs = [ setuptools-scm toml six astroid ];
+  propagatedBuildInputs = [ setuptools-scm six astroid ];
 
   checkInputs = [ pytest ];