test: fix strict CI gates

src/cli/update-cli/restart-helper.test.ts

@@ -21,7 +21,7 @@ describe("restart-helper", () => {
 
   async function prepareAndReadScript(env: Record<string, string>, gatewayPort = 18789) {
     const scriptPath = await prepareRestartScript(env, gatewayPort);
-    if (scriptPath === undefined) {
+    if (scriptPath == null) {
       throw new Error("expected restart script path");
     }
     const content = await fs.readFile(scriptPath, "utf-8");