QA Check Report - Shallow crawl check needs re-implementing

[ldbiz]

The shallow crawl check was removed temporarily as it was causing the report to fall over.

I think this is probably because there was no data in the test dataset (the test database appears to be several months out of date). However as the function is quite gnarly (pandas/lambda/apply), I've just commented it out so we can get the report running generally, this is a non-core check.

[ldbiz]

To reproduce:

Reinstate the function.
Use an out of date db dump (for null results).
Run the full report (-f) with lookback days that end since the db end date.

NB. Assuming that reproduces it, the empty set may be the cause, or it may just be one case - that needs to be investigated.