[Follow up to #38020] Expired sync QR code can be used on Android devices if the code is scanned before expiration time

[hffvld]

Description

Follow-up to #38020.

Steps to reproduce

1. Launch Brave on iOS or Android device
2. Open Settings > Sync
3. Start a new Sync Chain > Choose the mobile option to create a new QR Code
4. Take Android device > Scan the QR Code and keep Brave opened on the Waring screen
5. Wait for the QR code to expire (or change system time for testing purposes)
6. After QR code expired tap Yes on Android device > Observe it was added to the Sync chain

Actual result

Expired sync QR code can be used on Android devices if the code is scanned before the expiration time.

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2024-07-08_15-01-57.mp4

Expected result

Expired sync QR code must not be usable, and a new device can't be added to the sync chain by scanning it.

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2024-07-08_15-10-19.mp4

Reproduces how often

Easily reproduced

Brave version

Brave build: 1.69.83
Chromium: 127.0.6533.26 (Official Build) canary (64-bit)

Device

• Brand/Model: Pixel 7
• Android version: Android 15

Channel information

• release (stable)
• beta
• nightly

Reproducibility

• with Brave Shields disabled
• with Brave Rewards disabled
• in the latest version of Chrome

Miscellaneous information

cc @AlexeyBarabash