Support for minimal interacter networks (2D network with 1D topology)

[veenstrajelmer]

Is your feature request related to a problem? Please describe.
The minimal FM files as written by interacter have a 1D topology. Since the face_node_connectivity can be derived internally, this could still represent a 2D grid. A testcase for reading such a grid without faces was added in #515. However, the example file has a 1D topology, but instead the topology_dimension attribute is set to 2 instead of 1. This means it is read as a 2D grid, automatically filled with face_node_connectivity by meshkernel since the update in #574. This is however not a grid that interacter would create and it is also corrupt since a network with a 2D topology should already contain this face_node_connectivity.

Describe the solution you'd like

• consider prevent reading this corrupt grid. This can be done by passing the face_node_connectivity from the grid to meshkernel. In that case it will crash. And probably set the face_node_connectivity attribute back to non-optional.
• replace the file with a file with topology_dimension=1. This converts the testcase in what it was meant for, reading an interacter-style network.
• In that case the grid should be read as mesh1d by hydrolib-core. However, this will currently not happen since NCExplorer._retrieve_1d_keys checks also for coordinate_space attribute which is not present in this network. The is_mesh1d test should only depend on the topology_dimension. coordinate_space should instead be a property of the resulting mesh1d class.
• Decide whether we want hydrolib-core to read the minimal network as mesh1d or mesh2d. If 1d, reading and writing (as ugrid) will convert the network to 1D from an interacter/FM point of view, this is not desireable.