Add structured log statement for failed covidcast files

[krivard]

We currently log failed files from covidcast acquisition as:

handling  /common/covidcast/receiving/chng/20210227_state_smoothed_adj_outpatient_cli.csv
archiving as failed - chng

To make it possible to alert on these failed files, we need to put them into the structured log for easier processing by Elastic.

[melange396]

looks like this was done in #611