Follow up of #15967 - https://p2a.brave.com/ endpoints are not listed in any network traffic tools

[GeetaSarvadnya]

Description

Found while testing #15967
Confirm packets to the https://p3a.brave.com/ and https://p2a.brave.com/ endpoints are similar to what what sent before the change, encoded as a binary protocol buffer, instead of in a human-readable strings like the json enpoint receives.

Follow the test plan from Follow the test plan from brave/brave-core#11600

Steps to Reproduce

1. Open Charles or any other n/w traffic tools
2. Clean profile 1.36.x
3. Enable rewards
4. View an untargeted ad
5. P2A endpoint https://p2a.brave.com host is not listed in Charles

Actual result:

https://p2a.brave.com/ endpoints are not listed in any network traffic tools

Expected result:

https://p2a.brave.com/ endpoints should be listed in network traffic tools

Reproduces how often:

Easy

Brave version (brave://version info)

Brave	1.36.87 Chromium: 98.0.4758.87 (Official Build) beta (64-bit)
Revision	e4cd00f135fb4d8edc64c8aa6ecbe7cc79ebb3b2-refs/branch-heads/4758@{#1002}
OS	Windows 10 Version 21H2 (Build 19044.1503)

Version/Channel Information:

• Can you reproduce this issue with the current release? Yes
• Can you reproduce this issue with the beta channel? Yes
• Can you reproduce this issue with the nightly channel? Yes

Other Additional Information:

• 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

Miscellaneous Information:

cc: @rillian @moritzhaller @brave/legacy_qa

[stephendonner]

In case it's a helpful datapoint; while verifying on macOS in #15967, I retested my steps several times, and in doing so, noticed we send data to p2.brave.com after ~8-9 minutes from profile start.

I've had up to 6 of these pings appear in a single run, before (not captured here).

My steps:

1. run Charles Proxy
2. new profile
3. enable Rewards
4. open 5 or more new tabs
5. wait for your 1st ad
6. do nothing and let the P3A/P2A fill in!

example	example

I've found -- depending on user actions I've taken in a given session -- I've had to wait up to ~45 minutes for 36 metrics to roll in. How long has/have your session(s) been, @GeetaSarvadnya ?

[GeetaSarvadnya]

@stephendonner I have waited for ~15 mins and I have got 28 metrics Yesterday and I wasn't getting P2A pings. But today when I tried again I can see 6 P2A pings in Charles. Looks like P2A pings are working as expected. Closing the issue as invalid. @stephendonner Thanks for checking!

P2A pings:

p2a pings	brave://local-state p2a metrics