Web SPICE not working for ShadowCam

**ISIS version(s) affected**: 10.1.0_RC1

**Description**
Now that ShadowCam has made it into the public version of ISIS, it's time to test it! So far, it seems good except for SPICE.
```
wget https://pds.shadowcam.im-ldi.com/observation/2023/190/M029240108S/M029240108SE.cub
shadowcam2isis from=M029240108SE.cub to=M029240108S.raw.cub
spiceinit from=M029240108S.raw.cub web=true
```

Result:
```
spiceinit: Requesting Spice Data
100% Processed
**ERROR** An error occurred when talking to the server. The server encountered an unexpected error in SpiceClient.cpp at 592.
```

I can spiceinit a NAC image from this computer with the same version of ISIS with no problems, so I'm guessing the issue is that web SPICE isn't fully aware that ShadowCam exists. downloadIsisData seems to know how to get the ShadowCam data directory (at least the non-kernel parts), so it seems like this is hopefully just a matter of adjusting a flag or adding KPLO kernel-syncing to the server settings.

(Also maybe you could make the error messages more informative?)

Reproduce the failure with the ShadowCam download, shadowcam2isis, and spiceinit commands in the report. Start by inspecting SpiceClient.cpp around line 592, then trace the web SPICE request and the server settings for ShadowCam or KPLO kernel syncing. Done means web=true completes spiceinit for the reported image, with a more informative error if the request still fails.

Written by the indexing model from the issue text.