Allow UI configuration of entities exposed to voice_assistant (#91233)

* Allow UI configuration of entities exposed to voice_assistant

* Invalidate cache when settings change

* Add tests

* Expose entities to conversation by default

* Update tests

homeassistant/helpers/entity_registry.py

@@ -309,6 +309,26 @@ class RegistryEntry:
 
         hass.states.async_set(self.entity_id, STATE_UNAVAILABLE, attrs)
 
+    def async_friendly_name(self, hass: HomeAssistant) -> str | None:
+        """Return the friendly name.
+
+        If self.name is not None, this returns self.name
+        If has_entity_name is False, self.original_name
+        If has_entity_name is True, this returns device.name + self.original_name
+        """
+        if not self.has_entity_name or self.name is not None:
+            return self.name or self.original_name
+
+        device_registry = dr.async_get(hass)
+        if not (device_id := self.device_id) or not (
+            device_entry := device_registry.async_get(device_id)
+        ):
+            return self.original_name
+
+        if not (original_name := self.original_name):
+            return device_entry.name_by_user or device_entry.name
+        return f"{device_entry.name_by_user or device_entry.name} {original_name}"
+
 
 class EntityRegistryStore(storage.Store[dict[str, list[dict[str, Any]]]]):
     """Store entity registry data."""