ceph: Fix tests by adding back old required python libs. See #281858.

Fixes #241482.

Also fix test putting cluster in unhealthy `POOL_APP_NOT_ENABLED` state;
this seems to be the default state with Ceph 18.2.1 at least,
and it does not hurt to fix it now already in the way the Ceph docs say.

Also revert "nixosTests.ceph-single-node: remove dashboard check"

This reverts commit 41b27d7f4b.

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

@@ -4,6 +4,7 @@
 , callPackage
 , cargo
 , cffi
+, cryptography-vectors ? (callPackage ./vectors.nix { })
 , fetchPypi
 , hypothesis
 , iso8601
@@ -24,9 +25,6 @@
 , setuptoolsRustBuildHook
 }:
 
-let
-  cryptography-vectors = callPackage ./vectors.nix { };
-in
 buildPythonPackage rec {
   pname = "cryptography";
   version = "41.0.7"; # Also update the hash in vectors.nix