repart: if partition already exists, required size may not be multiple of grain size

See partition_min_size_with_padding().
Fixes #37178.

(cherry picked from commit cb109e00c4)

src/repart/repart.c

@@ -1073,7 +1073,6 @@ static bool context_allocate_partitions(Context *context, uint64_t *ret_largest_
 
                 /* How much do we need to fit? */
                 required = partition_min_size_with_padding(context, p);
-                assert(required % context->grain_size == 0);
 
                 /* For existing partitions, we should verify that they'll actually fit */
                 if (PARTITION_EXISTS(p)) {