Sync sends bookmarks even when chain is not fully created

[AlexeyBarabash]

Description

With Sync UI v2 sync chain is considered created when it has two or more devices.
Now we can see that bookmarks are sent even if there is only one device in chain, and the secon is not connected yet.

Steps to Reproduce

1. Launch brave browser in terminal
Sync lib output into terminal is not available on release build, so updating this STR

1. Create a bookmark.
2. Open brave://inspect/#extensions in tab
3. Open brave://sync/ page
4. Press Start a new sync chain button, don't add the second device to chain
5. Go back to brave://inspect/#extensions, Click inspect link under Brave Sync
6. Click [Console] tab
7. Look on console and wait

Actual result:

5. You will see messages saying bookmark records are sent to sync, like sending record: {"action":0,"bookmark":{ ...

Expected result:

5. No send to sync of bookmarks in this case, therefore no messages saying, bookmark records are sent to sync.

Reproduces how often:

Easyly

Brave version (brave://version info)

Brave	0.61.0 Chromium: 72.0.3626.17 (Developer Build) (64-bit)
Revision	08d2140079f8db14c9eb885a803d231b1a30e817-refs/branch-heads/3626@{#315}
OS	Linux

Reproducible on current release:

• Does it reproduce on brave-browser dev/beta builds?
  Reproduced on nightly for sure.

[srirambv]

@AlexeyBarabash is this similar to #2148. In #2148 bookmark sync was disabled but still ended up showing on the other device. This issue mentioned about the logs in console about sending records even though sync chain isnt created.

[AlexeyBarabash]

@srirambv
I think, #2687 is not similar to #2148.

#2687 is related to sync ui v2, when we have to force to have at least 2 devices in chain and show sync code (get seed) with a probability that sync chain will not be created.

#2148 happened because several bookmarks from b-c were sent before switching option off.

[LaurenWags]

Verified passed with

Brave	0.63.31 Chromium: 73.0.3683.75 (Official Build) beta(64-bit)
Revision	909ee014fcea6828f9a610e6716145bc0b3ebf4a-refs/branch-heads/3683@{#803}
OS	Mac OS X

• Verified STR from description. Reproduced issue on 0.62.x and verified did not see issue on 0.63.31.

Verification passed on

Brave	0.63.31 Chromium: 73.0.3683.75 (Official Build) beta (64-bit)
Revision	909ee014fcea6828f9a610e6716145bc0b3ebf4a-refs/branch-heads/3683@{#803}
OS	Windows 10 OS Build 17134.523

Used STR from description

Verification passed on

Brave	0.63.31 Chromium: 73.0.3683.75 (Official Build) beta (64-bit)
Revision	909ee014fcea6828f9a610e6716145bc0b3ebf4a-refs/branch-heads/3683@{#803}
OS	Linux

• Verified the STR from description