Always round up when computing L2 products' geo grid dimensions

[gmgunter]

The output geo grid of NISAR L2 products (except for the Static Layers product) is computed by the create() function in nisar/workflows/geogrid.py.

When determining the length and width of the geo grid, this function rounds each to dimension to the nearest integer.

https://github.com/isce-framework/isce3/blob/8cc6581525e608cc95fdcd883dac87e08f83e7d0/python/packages/nisar/workflows/geogrid.py#L299-L300

https://github.com/isce-framework/isce3/blob/8cc6581525e608cc95fdcd883dac87e08f83e7d0/python/packages/nisar/workflows/geogrid.py#L17-L25

In cases where this rounds down, the resulting geo grid will not include the full extents that were requested by the user in the input runconfig. The bottom_right corner will fall outside of the geo grid extents.

In order to avoid this, we should always round up instead of rounding to the nearest integer.