Add error response during map load

[rchampine]

These two Syracuse volumes refuse to load. It is possible to click "Load Volume" but the sheets aren't populating.
https://oldinsurancemaps.net/loc/sanborn06296_015/
https://oldinsurancemaps.net/loc/sanborn06296_016/

[mradamcox]

From the load log:

  File "..../ohmg/loc_insurancemaps/models.py", line 395, in make_sheets
    sheet_no=parsed.sheet_number,
AttributeError: 'LOCParser' object has no attribute 'sheet_number'

Need to look into the parser, either something got changed inadvertently or there is something abnormal about these particular records. Hopefully can get to it this evening or sometime tomorrow.

[rchampine]

Interesting — no rush on our end. There are plenty of other volumes we can work on.

[mradamcox]

Looks like there is a missing page on these two, which is causing the error. Should have better handling on the ingestion side for this, so I'll leave this ticket open for now.

[mradamcox]

To complete this, the load process needs to set "load error" as the map status when an error has occurred, and the frontend needs to be updated to look for this status and render the page accordingly.

[rchampine]

Hey Adam — these two Syracuse volumes are still stuck. I checked to see if the new loading process could help them but now it is currently impossible to open their Unprepared or Prepared sections. I'm guessing it's related to what's discussed on this thread.

[mradamcox]

@rchampine looks like there is an issue with the iiif_info property on one of the Documents. I'll look into this as soon as I can.