Support non-live database migration (#72433)

* Support non-live database migration

* Tweak startup order, add test

* Address review comments

* Fix typo

* Clarify comment about promoting dependencies

* Tweak

* Fix merge mistake

* Fix some tests

* Fix additional test

* Fix additional test

* Adjust tests

* Improve test coverage

homeassistant/components/recorder/util.py

@@ -552,7 +552,7 @@ def write_lock_db_sqlite(instance: Recorder) -> Generator[None, None, None]:
 
 
 def async_migration_in_progress(hass: HomeAssistant) -> bool:
-    """Determine is a migration is in progress.
+    """Determine if a migration is in progress.
 
     This is a thin wrapper that allows us to change
     out the implementation later.
@@ -563,6 +563,18 @@ def async_migration_in_progress(hass: HomeAssistant) -> bool:
     return instance.migration_in_progress
 
 
+def async_migration_is_live(hass: HomeAssistant) -> bool:
+    """Determine if a migration is live.
+
+    This is a thin wrapper that allows us to change
+    out the implementation later.
+    """
+    if DATA_INSTANCE not in hass.data:
+        return False
+    instance: Recorder = hass.data[DATA_INSTANCE]
+    return instance.migration_is_live
+
+
 def second_sunday(year: int, month: int) -> date:
     """Return the datetime.date for the second sunday of a month."""
     second = date(year, month, FIRST_POSSIBLE_SUNDAY)