Add tileX to regional diag_manager output

[uramirez8707]

Describe the bug The current diag_manager does not add "tileX" to the filename when using a cube sphere, which leads to trouble when trying to combine the files and regrid them (if the region is in two different tiles)

I think this is a bug that was introduced when fms2_io was implemented in the diag_manager, mpp_io's diag_manager was adding tileX.

To Reproduce Add a regional diagnostic to the diag_table with a test case that is in a cube_sphere domain. You will see .tileX is not in the filename. See helpdesk ticket #231128 for an example

Expected behavior Diag_manager should be adding tileX to the filename OR if regions in multiple tiles are not going to be supported there should be a clear error message.

This is the code to update: https://github.com/NOAA-GFDL/FMS/blob/1003bebef9f2884e92eb209c85ac7414ef5cd9e8/diag_manager/diag_output.F90#L139-L140

System Environment Describe the system environment, include: This happens in any system.

Additional context N/A