bottom roughness: Handle non-periodic longitude case in `fill_missing_data_laplace` for regional configurations

[minghangli-uni]

The existing implementation of fill_missing_data_laplace only supports periodic longitude that is global configurations. When periodic_lon_laplace=False, the function raises a NotImplementedError.

I'll implement a non-periodic longitude use case shortly.

[minghangli-uni]

close this as #113 is closed