AD mode currently blocked from being turned on when FATES is on

### Brief summary of bug

When `use_fates=.true.` the xmlchange `CLM_ACCELERATED_SPINUP=on` has no effect, and the `spinup_state` is automatically set to `0`.

If `spinup_state` is set to something other than `0` in `user_nl_clm` the build script fails with the error:

```
$log->fatal_error("spinup_state is accelerated (=1 or 2) which is for a BGC mode of CN or BGC," .
" but the BGC mode is Satellite Phenology, change one or the other");
```
see [here](https://github.com/ESCOMP/CTSM/blob/90bbcdb8eedb5cf78ccd27a53f142f096e871c2a/bld/CLMBuildNamelist.pm#L1274C1-L1275C95)

We need to rewrite this section of the `CLMBuildNamelist` so that we can use AD mode with FATES.

### General bug information

**CTSM version you are using:** latest

**Does this bug cause significantly incorrect results in the model's science?** Yes

**Configurations affected:** any AD mode