italy_anac: Missing release date

[jpmckinney]

Similar to #1028, some releases have no date. Not sure if we can copy another date into this field.

This causes an issue for the registry's exporter, which needs a date to fill the annual files.

(The undated data is still included in the "full" file.)

This is an issue as users might expect the individual years to add up to the full file.

Another option (which would fix this in the registry instead) is to build an "undated" file, to list for download.

[yolile]

cc @allakulov for reporting to the publisher

[sentry-io]

Sentry issue: REGISTRY-5C

[sentry-io]

Sentry Issue: REGISTRY-KINGFISHER-PROCESS-9Y