`cells_for_geo_points` doesn't work correctly with`dggs_vert0_lon` is set

[tik65536]

Problem:
When using cells_for_geo_points with dggs_vert0_lon set to 11.20, the resulting zone IDs are incorrect.

1. Get zone centroids and ID using grid_cell_centroids_for_extent with dggs_vert0_lon == 11.20,

2. Using the zone centroids from above as input to cells_for_geo_points with the same dggs_vert0_lon setting. The result zone IDs are different.

Finding:
It is found that when dggs_vert0_lon is set for the cells_for_geo_points, the meta file output for DGGRID consists of :

dggs_vert0_lon 11.2
dggs_vert0_lat None
dggs_vert0_azimuth None

The extra setting dggs_vert0_lat None causes DGGRID to return incorrect zone IDs. After the dggs_vert0_lat is removed, all zone IDs are identical to the grid_cell_centroids_for_extent result.

After checking, the problem arises in the following code segment:

dggrid4py/dggrid4py/dggrid_runner.py

Lines 989 to 992 in dc7bd3a

	if subset_conf:
	for elem, value in subset_conf.items():
	metafile.append(f"{elem} " + str(value))

A quick fix will be to only append the setting with the value != None

A long-term solution is to restructure the code similar to dgapi_grid_gen, but this would take some time.