pythonPackages.flask_cache: remove

The package is currently broken and most folks recommend to use
`flask-caching` (see
thadeusb/flask-cache#171).

The only package in `nixpkgs` which remained to use `flask_cache`
(`graphite_api`) still builds with `pythonPackages.flask-caching`.

The removal and corresponding `graphite_api` change unbreaks several
Hydra builds (see https://hydra.nixos.org/build/76953777).

pkgs/top-level/python-packages.nix

@@ -5499,23 +5499,6 @@ in {
 
   flask-babel = callPackage ../development/python-modules/flask-babel { };
 
-  flask_cache = buildPythonPackage rec {
-    name = "Flask-Cache-0.13.1";
-
-    src = pkgs.fetchurl {
-      url = "mirror://pypi/F/Flask-Cache/${name}.tar.gz";
-      sha256 = "90126ca9bc063854ef8ee276e95d38b2b4ec8e45fd77d5751d37971ee27c7ef4";
-    };
-
-    propagatedBuildInputs = with self; [ werkzeug flask ];
-
-    meta = {
-      homepage = https://github.com/thadeusb/flask-cache;
-      description = "Adds cache support to your Flask application";
-      license = "BSD";
-    };
-  };
-
   flask-caching = callPackage ../development/python-modules/flask-caching { };
 
   flask-common = callPackage ../development/python-modules/flask-common { };
@@ -15852,7 +15835,7 @@ EOF
 
     propagatedBuildInputs = with self; [
       flask
-      flask_cache
+      flask-caching
       cairocffi
       pyparsing
       pytz