Sometimes unable to dismiss the OK button to set up a Sync chain

[stephendonner]

Description

Sometimes unable to dismiss the OK button to set up a Sync chain

Steps to Reproduce

Do all of the following as quickly as you can, as I feel this might be a race condition:

1. new profile
2. launch Brave
3. immediately click on the hamburger menu and choose Sync
4. click on Set up a Sync chain
5. click on Computer
6. now click on OK

Actual result:

The OK button sometimes doesn't dismiss, and this is thrown in the console logs when it doesn't:

[18421:259:0617/112359.766021:ERROR:brave_sync_prefs.cc(124)] Encrypt sync seed failure [18421:259:0617/112359.766622:ERROR:CONSOLE(1282)] "Error setting sync code", source: chrome://settings/settings.js (1282)

Screencast (too big to attach): https://drive.google.com/file/d/1RhkQiN3QKq_JWOlRQ_jMV2Ffr4rPr2jR/view?usp=sharing

Expected result:

OK should dismiss the dialog, and the Sync chain should be set up

Reproduces how often:

Not 100%

Brave version (brave://version info)

Brave	1.26.63 Chromium: 91.0.4472.106 (Official Build) (x86_64)
Revision	574f7b38e4e7244c92c4675e902e8f8e3d299ea7-refs/branch-heads/4472@{#1477}
OS	macOS Version 11.4 (Build 20F71)

/cc @AlexeyBarabash