refactor CalendarChangedEvent with runtime.rs #8764

Job	Run time
desktop_ci (linux-x86_64, depot-ubuntu-22.04-8)	10m 20s
desktop_ci (macos, depot-macos-15)	12m 23s
desktop_ci (linux-aarch64, depot-ubuntu-22.04-arm-8)	14m 42s
ci	3s
	37m 28s

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