Drop two PrimaryProfilePin cases that only restate the constructor
defaults and blank-string normalisation, and the wiring-routing test that
froze POOL_LIMITS_SETTINGS_ROUTE to a literal string — a snapshot of the
constant, not a behaviour contract. The two kept pin tests cover the bug
(a live primary keeps answering for its booted profile after the stored
preference moves; teardown releases the pin), and the notifications tests
cover the toast action end-to-end.
7dec81568e