Reapply "PEOPLE: Duplicate Finder Memory Usage (#2824)"

This reverts commit 89cd893.

.gitignore

@@ -21,6 +21,7 @@ Gemfile.lock
 
 # reports
 spec/coverage
+coverage
 spec/reports
 brakeman-output.tabs
 rubocop-results.xml

app/domain/insieme/import/person_duplicate_finder.rb

@@ -10,23 +10,25 @@ module Import
     module PersonDuplicateFinder
       private
 
-      def duplicates(attrs)
+      def duplicate_ids_with_first_person(attrs)
         if attrs[:number].present?
-          ::Person.where(number: attrs[:number]).to_a.presence ||
-            check_duplicate_with_different_number(attrs, super)
+          people_ids = ::Person.where(number: attrs[:number]).pluck(:id).presence
+          return {people_ids:, first_person: find_first_person(people_ids)} if people_ids
+          check_duplicate_with_different_number(attrs, super)
         else
           super
         end
       end
 
-      def check_duplicate_with_different_number(attrs, duplicates)
-        if duplicates.present?
-          person = duplicates.first
-          add_duplicate_with_different_number_error(person) if person.number?
+      def check_duplicate_with_different_number(attrs, duplicate_ids_with_first_person)
+        duplicate_ids = duplicate_ids_with_first_person[:people_ids]
+        first_person = duplicate_ids_with_first_person[:first_person]
+        if duplicate_ids.present?
+          add_duplicate_with_different_number_error(first_person) if first_person.number?
         else
           attrs[:manual_number] = true
         end
-        duplicates
+        duplicate_ids_with_first_person
       end
 
       def add_duplicate_with_different_number_error(person)