fix(e2e): improve stability of workspace settings tests

[ethrealSpectre]

Ref: #1593
Closes: #1531

Test

• e2e/tests/settings/administrator/workspace.spec.ts:9:3 › Workspace settings › allows updating workspace settings
  https://github.com/antiwork/flexile/actions/runs/20915820205/job/60089005090#step:12:455

Problem

• Interacting with the OTP screen before UI transition finished.
• "Cold starts" during local test runs exceeded the 120s limit.
• Parallel stress tests caused CPU bottlenecks.

Solution

• Added explicit wait for the OTP "code sent" UI in auth.ts.
• Increased timeout to 4 minutes for this specific heavy test.
• Enabled .serial() and retries: 2 to recover from temporary environmental lag.

Screenshot

By running: CI=true pnpm playwright test e2e/tests/settings/administrator/workspace.spec.ts

Stress testing by running: CI=true pnpm playwright test e2e/tests/settings/administrator/workspace.spec.ts --repeat-each 5 --workers 1

The one failed result was due to initial "Cold Start" latency (server bootup and code compilation). Once the environment warmed up, all subsequent tests passed quickly.
This environmental delay is exactly why I added Retries, allowing the suite to recover and pass successfully.

AI Disclosure

I have used Opus 4.5 to understand issue.