nixosTests.installed-tests: allow passing extra makeTest args

For example, extra meta tags.

nixos/tests/installed-tests/default.nix

@@ -29,8 +29,14 @@ let
 
       # Extra flags to pass to gnome-desktop-testing-runner.
     , testRunnerFlags ? ""
-    }:
+
-    makeTest rec {
+      # Extra attributes to pass to makeTest.
+      # They will be recursively merged into the attrset created by this function.
+    , ...
+    }@args:
+    makeTest
+      (recursiveUpdate
+        rec {
           name = tested.name;
 
           meta = {
@@ -58,7 +64,16 @@ let
                   "gnome-desktop-testing-runner ${testRunnerFlags} -d '${tested.installedTests}/share'"
               )
             '';
-    };
+        }
+
+        (removeAttrs args [
+          "tested"
+          "testConfig"
+          "preTestScript"
+          "withX11"
+          "testRunnerFlags"
+        ])
+      );
 
 in