[Sync v2] Device removed from sync chain when offline is still listed on the other device

[srirambv]

Description

Offline device isn't removed from list even when its removed from sync chain

Steps to reproduce

1. Create a sync chain between device A and scan QR code on device B to add it to sync chain
2. Disconnect device B from network
3. Leave sync chain on device B
4. You'll run into [Android] Trying to leave sync chain when offline doesn't warn user about network  #11165
5. Check device A both devices are still listed
6. Bring device B online and ensure sync chain is removed. Verify in sync-internals as well
7. Device A still lists both the devices
8. Quit and relaunch browser on device A still has device B in the list

Actual result

Device removed from sync chain when offline is still listed on the other device

Expected result

Should remove device from the list

Issue reproduces how often

Easy

Version/Channel Information:

• Can you reproduce this issue with the current Play Store version? NA
• Can you reproduce this issue with the current Play Store Beta version? Yes
• Can you reproduce this issue with the current Play Store Nightly version? Yes

Device details

• Install type (ARM, x86): ARM
• Device type (Phone, Tablet, Phablet): All
• Android version: All

Brave version

1.12.111

Website problems only

• Does the issue resolve itself when disabling Brave Shields? NA
• Does the issue resolve itself when disabling Brave Rewards? NA
• Is the issue reproducible on the latest version of Chrome? NA

Additional information

Issue found while testing #10198

[AlexeyBarabash]

I can reproduce the issue

[LaurenWags]

Not specific to Android, encountered this while testing #19199 on desktop.

Steps:

1. Start a sync chain on one device (A)
2. Join sync chain with second device (B)
3. Disable network
4. Leave sync chain on Device A
5. Device A returns to pre-sync state
6. Re-enable network
7. Wait for Device B to recognize that Device A is no longer part of the chain
   ---> Step 7 never happens, continues to show 2 devices

[btlechowski]

Looks similar to #10879