repo: delete rows in `lfs_object` table when delete repo (#6072)

internal/db/repo.go

@@ -1566,6 +1566,7 @@ func DeleteRepository(ownerID, repoID int64) error {
 		&ProtectBranchWhitelist{RepoID: repoID},
 		&Webhook{RepoID: repoID},
 		&HookTask{RepoID: repoID},
+		&LFSObject{RepoID: repoID},
 	); err != nil {
 		return fmt.Errorf("deleteBeans: %v", err)
 	}