Ensure all data is set in seventeentrack before adding entities (#111603)

This integration would call async_add_entities before
it has set the data that the entity needed. There is
no guarantee that the entity would take long enough
to add that the data would be there

homeassistant/components/seventeentrack/sensor.py

@@ -21,6 +21,7 @@ from homeassistant.core import HomeAssistant
 from homeassistant.helpers import (
     aiohttp_client,
     config_validation as cv,
+    entity,
     entity_registry as er,
 )
 from homeassistant.helpers.entity_platform import AddEntitiesCallback
@@ -293,6 +294,7 @@ class SeventeenTrackData:
 
     async def _async_update(self):
         """Get updated data from 17track.net."""
+        entities: list[entity.Entity] = []
 
         try:
             packages = await self._client.profile.packages(
@@ -306,12 +308,9 @@ class SeventeenTrackData:
 
             _LOGGER.debug("Will add new tracking numbers: %s", to_add)
             if to_add:
-                self._async_add_entities(
-                    [
-                        SeventeenTrackPackageSensor(self, new_packages[tracking_number])
-                        for tracking_number in to_add
-                    ],
-                    True,
+                entities.extend(
+                    SeventeenTrackPackageSensor(self, new_packages[tracking_number])
+                    for tracking_number in to_add
                 )
 
             self.packages = new_packages
@@ -327,15 +326,13 @@ class SeventeenTrackData:
             # creating summary sensors on first update
             if self.first_update:
                 self.first_update = False
-
-                self._async_add_entities(
-                    [
-                        SeventeenTrackSummarySensor(self, status, quantity)
-                        for status, quantity in self.summary.items()
-                    ],
-                    True,
+                entities.extend(
+                    SeventeenTrackSummarySensor(self, status, quantity)
+                    for status, quantity in self.summary.items()
                 )
 
         except SeventeenTrackError as err:
             _LOGGER.error("There was an error retrieving the summary: %s", err)
             self.summary = {}
+
+        self._async_add_entities(entities, True)