mesh read multiple open calls

@EdHone is already working on this.

Since Jul 8, 2026.

when reading data from mesh files, the `lfric_core` code places the file open calls within a call structure which results in a rank opening the file numerous times during the mesh reading

this puts unhelpful load on parallel file systems at scale.

The mesh reading netCDF interface code should be refactored such that reading, whether a full mesh or pre-partitioned mesh, requires only one open call, that is safely closed on completion or error.

The key loop is within [load_global_mesh_multiple](https://github.com/MetOffice/lfric_core/blob/main/components/driver/source/mesh/load_global_mesh_mod.f90#L39)

Which is iterated over mulitple times, with `N` epending on the configuration (e.g. C224 `lfric_atm` test this is called 5 times)

The problem is that the actual file interactions are located further down the call stack:
```
#9 file_open$ncdf_quad_mod_ +0x8de [0x11671ae]
#10 set_from_file_read$ugrid_2d_mod_ +0x15e [0x119530e]
#11 read_from_file$ugrid_mesh_data_mod_ +0xa8e [0x6d04de]
#12 load_global_mesh_single$load_global_mesh_mod_ +0x83e [0x67325e]
#13 load_global_mesh_multiple$load_global_mesh_mod_ +0x59 [0x672a09]
#14 init_mesh$driver_mesh_mod_ +0x1b55 [0x4f4ad5]
#15 initialise_infrastructure$gungho_model_mod_ +0x4740 [0x4afb00]
#16 initialise$gungho_driver_mod_ +0xa1a [0x489cba]
```

So, a redesign and re-implementation is needed.

Success Criteria:
* The netCDF file is only opened once, and accessed multiple times, not opened and closed for each element within this loop.

The open code is located within: [file_open](https://github.com/MetOffice/lfric_core/blob/main/infrastructure/source/io/ncdf_quad_mod.F90#L229)

which is called from [set_from_file_read](https://github.com/MetOffice/lfric_core/blob/main/infrastructure/source/io/ugrid_2d_mod.F90#L496C12-L496C30)

(note that [check_error](https://github.com/MetOffice/lfric_core/blob/main/infrastructure/source/io/ncdf_quad_mod.F90#L1807) could be used to manage the `also close on failure` case)