fix: avoid reusing servers for e2e tests (#2558)

Hoping to make the `Console e2e` tests more stable.

frontend/playwright.config.ts

@@ -38,6 +38,6 @@ export default defineConfig({
   webServer: {
     command: 'ftl dev --recreate',
     url: 'http://localhost:8892',
-    reuseExistingServer: true,
+    reuseExistingServer: !process.env.CI,
   },
 });