Update power level default for public rooms #398

Job	Run time
changes	4s
lint-crlf	3s
lint-newsfile	34s
check-lockfile	7s
Typechecking	1m 22s
check-schema-delta	41s
check-sampleconfig	43s
lint	50s
lint-pydantic	2m 21s
lint-clippy	0s
lint-clippy-nightly	0s
lint-rustfmt	0s
linting-done	3s
calculate-test-jobs	5s
trial-olddeps	6m 50s
portdb (3.8, 11)	2m 51s
complement (monolith, SQLite)	12m 17s
portdb (3.11, 15)	2m 39s
complement (monolith, Postgres)	12m 55s
cargo-bench	0s
complement (workers, Postgres)	19m 39s
cargo-test	0s
trial-pypy	0s
trial (3.8, sqlite, all)	4m 13s
sytest (focal)	8m 9s
trial (3.8, postgres, 11, all)	9m 48s
sytest (focal, postgres)	10m 35s
trial (3.8, sqlite)	3m 46s
sytest (focal, multi-postgres, workers)	13m 44s
sytest (focal, multi-postgres, workers, asyncio)	19m 14s
export-data	2m 7s
tests-done	3s
	2h 15m 43s

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