Include synced history entries into P3A

[AlexeyBarabash]

Currently Brave.Sync.SyncedObjectsCount P3A metric doesn't include statistic for History, because SyncServiceImpl::GetEntityCountsForDebugging doesn't include that.

History is the most consuming datatype and it is vital to know the statistics.

[kjozwiak]

The above requires 1.62.165 or higher for 1.62.x verification 👍

[GeetaSarvadnya]

Verification PASSED on

Brave | 1.62.165 Chromium: 121.0.6167.184 (Official Build) (64-bit)
-- | --
Revision | 646e9a49ef45084cb2341eb1e9afabc339004a27
OS | Windows 10 Version 22H2 (Build 19045.3930)

• Verified the test plan from Include synced history entries into P3A brave-core#21623
• Confirmed that the metrics SyncedObjectsCount response value is 0 when sync chain is created and History is enabled

Example	Example

• Confirmed that the metrics SyncedObjectsCount response value is 1 after following the steps 3 to 7
  

[GeetaSarvadnya]

Verification PASSED on Samsung galaxy version 12 running Bravemonoarm64.apk_1.62.165

• Verified the test plan from Include synced history entries into P3A brave-core#21623
• Confirmed that the metrics SyncedObjectsCount response value is 0 when sync chain is created and History is enabled

Example	Example	Example

• Steps 3-7 are not verified, see the comments Include synced history entries into P3A #35579 (comment)

[GeetaSarvadnya]

@AlexeyBarabash As per my discussion with @deeppandya we can't verify brave://inspect/#extensions on Android hence we will not be able to verify the steps 3 to 7 (from brave/brave-core#21623) on Android. Hence we are skipping the steps 3-7 verification on Android. Let us know if you know any alternatives I can verify from my end.

cc: @kjozwiak @LaurenWags

[AlexeyBarabash]

@GeetaSarvadnya
This is fine to verify on Desktop only.
There is no way to make good test plan on Android.

thanks.