Landunit *1d_ityp* variable long names are incorrect

### Brief summary of bug

https://github.com/ESCOMP/CTSM/blob/e1f563b8345400d33421263f05b237f13e6b0e3d/src/main/histFileMod.F90#L3883-L3885

https://github.com/ESCOMP/CTSM/blob/e1f563b8345400d33421263f05b237f13e6b0e3d/src/main/histFileMod.F90#L3913-L3915

https://github.com/ESCOMP/CTSM/blob/e1f563b8345400d33421263f05b237f13e6b0e3d/src/main/histFileMod.F90#L3952-L3954

The values are listed as "vegetated,urban,lake,wetland,glacier or glacier_mec", but this is incorrect. Based on the global `ltype_*` attributes, it should be "vegetated/bare soil, crop, ocean, landice, deep lake, wetland, urban tbd, urban hd, or urban md."

Even better would be to not list these at all, instead referring the user to the global attributes.

### General bug information

**CTSM version you are using:** ctsm5.4.038

**Does this bug cause significantly incorrect results in the model's science?** No

**Configurations affected:** n/a

### Important output or errors that show the problem
From `ncdump`:
```
land1d_ityplunit:long_name = "landunit type (vegetated,urban,lake,wetland,glacier or glacier_mec)" ;
...
cols1d_itype_lunit:long_name = "column landunit type (vegetated,urban,lake,wetland,glacier or glacier_mec)" ;
...
pfts1d_itype_lunit:long_name = "pft landunit type (vegetated,urban,lake,wetland,glacier or glacier_mec)" ;
```