cync_lan (Home Assistant custom_component) v2.5.2

Fixes every bridge button showing up as "Cync LAN Bridge" - the same fault
2.5.1 fixed for group power switches, which turned out to be more widespread
than that release assumed.

All six home-wide button types were affected: Query mesh credentials, Sync hub
clock, and the Delete buttons for scenes, schedules, automation bindings and
groups. Since there is one Delete button per scene, schedule and group, a
populated account produced a long list of buttons with the same name and no
way to tell which was which.

They all inherit from one base class that was missing has_entity_name, so
this is a one-line fix covering all six rather than six separate ones.

Also adds a test that scans the source for the general mistake - an entity
declaring a translated name without the flag that makes it apply - rather than
checking the eight classes known to have hit it. The same bug reaching a
release twice is what prompted it.