Narrow message_handler's parameter to notifications and exceptions #3656

Job	Run time
checks / readme-snippets	15s
checks / docs	1m 7s
checks / pre-commit	1m 1s
checks / test (3.11, lowest-direct, windows-latest)	1m 49s
checks / test (3.10, locked, windows-latest)	1m 44s
checks / test (3.12, lowest-direct, windows-latest)	2m 5s
checks / test (3.14, locked, ubuntu-latest)	1m 22s
checks / test (3.14, locked, windows-latest)	2m 53s
checks / test (3.12, locked, windows-latest)	1m 54s
checks / test (3.12, locked, ubuntu-latest)	1m 40s
checks / test (3.11, locked, windows-latest)	2m 3s
checks / test (3.13, locked, ubuntu-latest)	1m 18s
checks / test (3.13, lowest-direct, windows-latest)	2m 0s
checks / test (3.10, lowest-direct, ubuntu-latest)	1m 33s
checks / test (3.13, lowest-direct, ubuntu-latest)	1m 20s
checks / test (3.12, lowest-direct, ubuntu-latest)	1m 28s
checks / test (3.10, lowest-direct, windows-latest)	2m 6s
checks / test (3.14, lowest-direct, ubuntu-latest)	1m 23s
checks / test (3.13, locked, windows-latest)	1m 53s
checks / test (3.10, locked, ubuntu-latest)	1m 25s
checks / test (3.11, lowest-direct, ubuntu-latest)	1m 26s
checks / test (3.14, lowest-direct, windows-latest)	1m 54s
checks / test (3.11, locked, ubuntu-latest)	1m 23s
all-green	5s
	37m 7s

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