treewide: remove superfluous disabled

There is no need to disable Python packages for Python versions that are
no longer in Nixpkgs.
This change was generated using the following script:

    pattern='^\s*disabled\s*=\s*pythonOlder\s*"3\.\([0-9]\|10\)"\s*;\s*$'
    for f in $(find -name '*.nix'); do
        grep -q "$pattern" "$f" || continue
        sed -i "/$pattern/d" "$f"
        if [ $(grep -c pythonOlder "$f") == 1 ]; then
            sed -i '/^\s*pythonOlder,\s*$/d' "$f"
        fi
        nixfmt "$f"
    done

pkgs/development/interpreters/python/tests/test_nix_pythonprefix/typeddep/default.nix

@@ -1,7 +1,6 @@
 {
   lib,
   buildPythonPackage,
-  pythonOlder,
 }:
 
 buildPythonPackage {
@@ -18,6 +17,4 @@ buildPythonPackage {
     ];
   };
 
-  disabled = pythonOlder "3.7";
-
 }