NoMethodError: undefined method `filter' for nil:NilClass

[sentry-io]

Sentry Issue: AGROPORTAL-UI-6G

NoMethodError: undefined method `filter' for nil:NilClass

    concepts.filter { |c| !concept_date(c).nil? }
            ^^^^^^^
  app/controllers/concepts_controller.rb:164:in `filter_concept_with_no_date'
    concepts.filter { |c| !concept_date(c).nil? }
  app/controllers/concepts_controller.rb:122:in `show_date_sorted_list'
    @concepts = filter_concept_with_no_date(@page.collection)
...
(93 additional frame(s) were not displayed)

This issue was automatically created by Sentry via UI issues

[imadbourouche]

we should handle the concepts when they are nil in

  def filter_concept_with_no_date(concepts)
    concepts.filter { |c| !concept_date(c).nil? }
  end