Additional Config Store Cleanup (#16440)

This change addresses a few issues where config stores were not
properly closed when an error was encountered on server startup.
This could result in leaked database connections when dealing with
a database config store.

config/store.go

@@ -54,7 +54,13 @@ func NewStore(dsn string, watch bool, customDefaults *model.Config) (*Store, err
 		return nil, err
 	}
 
-	return NewStoreFromBacking(backingStore, customDefaults)
+	store, err := NewStoreFromBacking(backingStore, customDefaults)
+	if err != nil {
+		backingStore.Close()
+		return nil, errors.Wrap(err, "failed to create store")
+	}
+
+	return store, nil
 }
 
 func NewStoreFromBacking(backingStore BackingStore, customDefaults *model.Config) (*Store, error) {