Add NTP-SI P3A reporting

[DJAndries]

Description:

Add NTP-SI P3A reporting for iOS. See brave/brave-browser#24609 for implementation details on Desktop + Android. Also see internal spec for more conceptual details

[tmancey]

FYI: For landed iOS would need to start a 10 second timer for now. The ads library does not inform the browser if an ad was landed.

[hffvld]

Verified on iPhone 14 using version(s):

Device/OS: iPhone 14 [iOS 16.6]
Brave build: 1.57 (23.8.16.21)
BraveCore: 1.57.47 (116.0.5845.96)

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STEPS:

1. Fresh launch Brave Dev build
2. Settings > BraveCore Switches > P3A section
3. Enable Don't randomize upload interval > Set Express rotation interval to a low number (I set it to 3) > Save
4. Go back to Settings > View Chromium Local State > Refresh > Verify there are no creativeInstanceId. records under p3a section
5. Now go back and open NTP > Keep open NTP until SI is shown
6. Open SI page > Wait ~10 seconds
7. Go to Settings > View Chromium Local State > Refresh > Verify creativeInstanceId. records with suffixes views, clicks and lands are shown
8. Delete and reinstall Brave
9. Now enable Rewards first:

• Settings > BraveCore Switches > Log Verbosity > Paste the following: /brave_ads/=6,/bat_ads/=6,/brave_rewards/=6,/bat-native-ledger/=6
• Return to Settings > View Rewards Debug Menu > Switch Override from None to Staging > Restart Brave
• Enable Rewards

10. Repeat Steps 2 - 7 > Verify there are no creativeInstanceId. records with suffixes views, clicks and lands are shown at this time

ACTUAL RESULTS:

• Verified that there are no creativeInstanceId. records under p3a section when Rewards is OFF and no SI viewed
• Verified that creativeInstanceId. records with suffixes views, clicks and lands are shown when Rewards is OFF and SI viewed
• Verified that there are no creativeInstanceId. records under p3a section when Rewards is ON and SI viewed

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Rewards is OFF

1	2	3

Rewards is ON

1	2	3	4