fix: Make breadcrumbs option optional in WinterCGFetch integration

[kamilogorek]

Right now it's not possible to use it as:

new Sentry.Integrations.WinterCGFetch({
  shouldCreateSpanForRequest: (url) => {
    return !url.startsWith(`${process.env.NEXT_PUBLIC_SUPABASE_URL}/rest`);
  }
})

due to breadcrubs not being marked as optional. Instead of changing it to such, reuse already existing Options interface to keep it in sync with the integration itself.

[Lms24]

Good catch, thx!

The class version of this integration will be gone soon anyway but we can merge this in and backport it to our v7 branch, which is where we should really fix this. Would you mind throwing up another PR for that @kamilogorek?