chore(electron): disable parallel execution of electron tests (#7789)

tests/affine-desktop/playwright.config.ts

@@ -16,7 +16,7 @@ import type { PlaywrightTestConfig } from '@playwright/test';
 const config: PlaywrightTestConfig = {
   testDir: './e2e',
   fullyParallel: true,
-  workers: 2,
+  workers: 1,
   timeout: process.env.CI ? 50_000 : 30_000,
   expect: {
     timeout: process.env.CI ? 15_000 : 5_000,