Sync devices page is frozen if you provide a custom sync URL that is invalid and try to start a chain

[MadhaviSeelam]

Description

Found while testing #12314. After configuring sync server via brave://settings/braveSync and enabling sync, several issues found. Page is frozen. Could not scroll thru page. Device name is not listed. Sync data toggles show icon for managed setting This setting is managed by your administrator but the message on the page is not shown.

Steps to reproduce

1. Installed 1.75.115
2. launched Brave
3. opened brave://settings/braveSync in a new tab
4. entered https://github.com/brave/go-sync in the text field Custom sync URL
5. clicked Relaunch button
6. confirmed Custom Sync URL field is populated with the set value but not grayed out and editable
7. clicked Start using sync tab above Custom sync URL tab
8. clicked Start a new Sync Chain >> Computer
9. clicked OK on Sync Chain code

Actual result

Manage your synced devices page is shown

• Page is frozen
• Can't scroll up/down on the page
• Device names are not listed.
• Sync data toggles show icon for managed setting This setting is managed by your administrator but the message on the page is not shown.

Expected result

Page should load as expected

Reproduces how often

Easily reproduced

Brave version (brave://version info)

Brave	1.75.115 Chromium: 132.0.6834.57 (Official Build) nightly (64-bit)
Revision	190df443fcce0f6b7941b8585b756b171f690448
OS	Windows 11 Version 24H2 (Build 26100.2314)

Channel information

• release (stable)
• beta
• nightly

Reproducibility

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

Miscellaneous information

@bsclifton

[bsclifton]

Likely due to this not being a valid sync URL. Someone would need to have a real instance of the sync software setup and ready to accept traffic for sync to actually work.

Behavior expected - but we could handle this better (ex: we can show an error about how server not responding, etc).

More info should show on brave://sync-internals

[bsclifton]

cc: @rebron @fmarier for triage (P4?)

[bsclifton]

Closing as this was reverted with brave/brave-core#27136