Ensure string in field test (#20777)

app/services/email_digest_article_collector.rb

@@ -78,6 +78,6 @@ class EmailDigestArticleCollector
   def results_count
     return 6 unless FeatureFlag.enabled?(:digest_results_count_testing)
 
-    (field_test(:digest_count_03_18, participant: @user) || 6).to_i
+    (field_test(:digest_count_03_18, participant: @user)&.split("_")&.last || 6).to_i
   end
 end

config/field_test.yml

@@ -30,12 +30,12 @@ experiments:
   digest_count_03_18:
     started_at: 2024-03-18
     variants:
-      - 6
-      - 4
-      - 5
-      - 7
-      - 8
-      - 10
+      - count_6
+      - count_4
+      - count_5
+      - count_7
+      - count_8
+      - count_10
     weights:
       - 60
       - 8