Setup clean setting state before every playwright test

[huchenlei]

Resolves #1302

Setup clean setting state before every playwright test. Cleanup logic like following code should no longer be necessary.

  test.afterEach(async ({ comfyPage }) => {
    await comfyPage.setSetting('Comfy.CustomColorPalettes', {})
    await comfyPage.setSetting('Comfy.ColorPalette', 'dark')
    await comfyPage.setSetting('Comfy.Node.Opacity', 1.0)
  })