Remove images from message notification e-mails. #2822

Job	Run time
changes	2s
check-lockfile	6s
lint-newsfile	32s
lint-crlf	3s
lint	46s
check-sampleconfig	46s
check-schema-delta	39s
lint-pydantic	40s
Typechecking	1m 25s
lint-clippy-nightly	0s
lint-readme	0s
lint-clippy	0s
lint-rustfmt	0s
linting-done	3s
calculate-test-jobs	6s
trial-olddeps	7m 36s
complement (monolith, SQLite)	12m 51s
portdb (3.8, 11)	2m 49s
complement (monolith, Postgres)	13m 13s
portdb (3.11, 15)	2m 44s
trial-pypy	0s
complement (workers, Postgres)	20m 58s
cargo-bench	0s
cargo-test	0s
sytest (focal)	8m 51s
trial (3.8, sqlite, all)	5m 4s
sytest (focal, postgres)	10m 14s
trial (3.8, postgres, 11, all)	12m 2s
sytest (focal, multi-postgres, workers)	13m 5s
trial (3.8, sqlite)	4m 42s
sytest (focal, multi-postgres, workers, asyncio)	19m 17s
export-data	2m 5s
tests-done	3s
	2h 20m 42s

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