Run each e2e test in a new workspace

The workspaces also have settings to prevent the welcome page from
appearing.

test/playwright.config.ts

@@ -6,7 +6,7 @@ import path from "path"
 const config: PlaywrightTestConfig = {
   testDir: path.join(__dirname, "e2e"), // Search for tests in this directory.
   timeout: 60000, // Each test is given 60 seconds.
-  retries: 3, // Retry failing tests 2 times
+  retries: process.env.CI ? 2 : 1, // Retry twice in CI due to flakiness.
   workers: 1,
   globalSetup: require.resolve("./utils/globalSetup.ts"),
   reporter: "list",
@@ -34,10 +34,4 @@ const config: PlaywrightTestConfig = {
   ],
 }
 
-if (process.env.CI) {
-  // In CI, retry failing tests 2 times
-  // in the event of flakiness
-  config.retries = 2
-}
-
 export default config