Add pixel definitions for contingency and browser menu

[CrisBarreiro]

Task/Issue URL:
Tech Design URL (if applicable): https://app.asana.com/1/137249556945/project/1212227266948491/task/1216264344628719?focus=true

Description

Steps to test this PR

Feature 1

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UI changes

Before	After
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Note

Low Risk
Telemetry schema and enum additions only; no runtime behavior, auth, or ad-blocking logic changes in this PR.

Overview
Adds 12 new YouTube ad blocking pixels (daily + count pairs) so product can measure browsing-menu enable/disable flows, disable-mode picker choices, and breakage reporting after a menu-driven disable.

ad_blocking.json5 registers events for: re-enable from the menu, opening the disable picker, picker options Always On, Always Off, and Disable Until Relaunch, plus Report Broken Site on the post-disable prompt. AdBlockingPixelNames mirrors each name with matching enum constants for app code to fire later.

This diff is definitions only—no new pixel firing or UI logic in the changed files.

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[CrisBarreiro]

• Submit ad-blocking menu strings for translation #9147
• Add view stub for ad blocking menu actions #9135
• Add ad-blocking menu item stub #9134
• Add pixel definitions for contingency and browser menu #9097 👈 (View in Graphite)
• Extract ad blocking domain matcher #9145 : 2 other dependent PRs (#9083 , #9137 )
• develop

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[github-actions]

Privacy Review task: https://app.asana.com/0/69071770703008/1216264345184702