Fix names for A/B test percentages

The dictionaries defining the A/B test percentages were incorrectly
namaed in a3a52ac.

Updating them to remove the underscores.

Author: brucebolt

dictionaries.yaml

@@ -19,15 +19,15 @@ example_percentages:
 bankholidaystest_percentages:
   A: 99
   B: 1
-graphql_ministers_index_percentages:
+graphqlministersindex_percentages:
   A: 0
   B: 0
   Z: 100
-graphql_news_articles_percentages:
+graphqlnewsarticles_percentages:
   A: 0
   B: 0
   Z: 100
-graphql_roles_percentages:
+graphqlrolespercentages:
   A: 0
   B: 0
   Z: 100