feat(git-resolver): fix private git repo (#6832)

fixes #6827
closes #6829

resolving/git-resolver/__mocks__/@pnpm/fetch.js

@@ -0,0 +1,6 @@
+module.exports = jest.createMockFromModule('@pnpm/fetch')
+
+// default implementation
+module.exports.fetch.mockImplementation(async (_url, _opts) => {
+  return { ok: true }
+})