Do not import from config in unit tests

extensions/ql-vscode/test/factories/config.ts

@@ -1,11 +1,10 @@
 import type { VariantAnalysisConfig } from "../../src/config";
-import { GITHUB_URL } from "../../src/config";
 
 export function createMockVariantAnalysisConfig(): VariantAnalysisConfig {
   return {
     controllerRepo: "foo/bar",
     showSystemDefinedRepositoryLists: true,
-    githubUrl: GITHUB_URL,
+    githubUrl: new URL("https://github.com"),
     onDidChangeConfiguration: jest.fn(),
   };
 }