Check if the showcase is still available before validating

Would it possible to add an additional check for the existing of the showcase here, something like:
`
# check if showcase_id is in context or is valid
if 'package' not in context or not context['package']:
log.warning("Showcase is not available. Showcase ID: {0}".format(
data_dict.get('showcase_id')))
return []
`

We have the situations that the showcase was deleted and was not reindexed, so we still get the deleted-showcase id here and try to validate it

Start by locating the showcase validation entry point that receives context and data_dict, then trace how a deleted, un reindexed showcase reaches it. Reproduce that case and verify that missing or invalid showcase context is skipped with a warning and an empty result instead of being validated.

Written by the indexing model from the issue text.