File storage usage default 0 (#20454)

* check for test fail in CI

* use 0 if there are no fileinfo table entries

* fix usage

store/sqlstore/file_info_store.go

@@ -739,7 +739,7 @@ func (fs SqlFileInfoStore) GetFilesBatchForIndexing(startTime int64, startFileID
 
 func (fs SqlFileInfoStore) GetStorageUsage(allowFromCache, includeDeleted bool) (int64, error) {
 	query := fs.getQueryBuilder().
-		Select("SUM(Size)").
+		Select("COALESCE(SUM(Size), 0)").
 		From("FileInfo")
 
 	if !includeDeleted {