test(benshi): read no list where a test counts

[noctuum]

On default settings the daemon of a binary test also runs the task that reads the AniList list. It says a line and connects to the session bus beside detection, so a test that counts either can count the list's.

• a_task_is_told_of.rs read detection's line by its place, and its two tests failed in 4 and 1 runs of 20.
• a_daemon_nobody_reads_starts_detection_again counted the list's connection as one of detection's, and passed with detection started again once in place of twice.

These tests now run on settings that read the list at no time, from reading_nothing in tests/common/mod.rs. a_task_is_told_of passed 60 runs of 60, and the second test fails when detection is started again only once.

cargo test --workspace passes, 1070 tests.