chore(e2e): use 1 worker for e2e test

I don't know if it's a resources issue, playwright, or code-server but it seems
like the e2e tests choke when multiple workers are used.

This change is okay because our CI runner only has 2 cores so it would only use
1 worker anyway, but by specifying it in our playwright config, we ensure more
stability in our e2e tests working correctly.

See these PRs:
- #3263
- #4310

Author: jsjoeio

test/playwright.config.ts

@@ -7,6 +7,7 @@ const config: PlaywrightTestConfig = {
   testDir: path.join(__dirname, "e2e"), // Search for tests in this directory.
   timeout: 60000, // Each test is given 60 seconds.
   retries: process.env.CI ? 2 : 1, // Retry in CI due to flakiness.
+  workers: 1,
   globalSetup: require.resolve("./utils/globalSetup.ts"),
   reporter: "list",
   // Put any shared options on the top level.