unifi: remove unifiTesting

The testing branch is not updated anymore and all mentions have been
removed from the Ubiquiti website.

pkgs/servers/unifi/default.nix

@@ -54,11 +54,4 @@ in rec {
     version = "5.11.39";
     sha256 = "0v1gnvdazxa3bcbq8hl6796yw0mxzki2xn4s5im5k5ngmfmnswyj";
   };
-
-  # TODO: update as it is outdated
-  unifiTesting = generic {
-    version = "5.11.18";
-    suffix = "-996baf2ca5";
-    sha256 = "14yyfn39ix8bnn0cb6bn0ly6pqxg81lvy83y40bk0y8vxfg6maqc";
-  };
 }

pkgs/top-level/all-packages.nix

@@ -15253,8 +15253,7 @@ in
 
   inherit (callPackages ../servers/unifi { })
     unifiLTS
-    unifiStable
-    unifiTesting;
+    unifiStable;
   unifi = unifiStable;
 
   virtlyst = libsForQt5.callPackage ../servers/web-apps/virtlyst { };