feat: add AdEvent message and related enums for ingesting ad event data #109268

Job	Run time
CI (ubuntu-latest, 3.4, --test)	1m 41s
CI (macos-latest, 4.0, --test)	55s
CI (ubuntu-latest, 3.2, --test)	1m 23s
CI (ubuntu-latest, 3.3, --test)	1m 26s
CI (windows-latest, 4.0, --test)	3m 3s
CI (ubuntu-latest, 4.0, --test)	1m 19s
CI (ubuntu-latest, 4.0, --rubocop-toplevel --rubocop --build --yard)	1m 38s
	11m 25s

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