Apply suggestions from code review

Co-authored-by: Frank Bertsch <frank.bertsch@gmail.com>

sql/moz-fx-data-shared-prod/firefox_ios_derived/app_store_funnel_web_referrer_v1/metadata.yaml

@@ -1,4 +1,4 @@
-friendly_name: Funnel iOS (web_referrer + campaign)
+friendly_name: Firefox iOS App Store Funnel
 description: |
   Derived dataset for supporting (Apple) app store funnel analysis (iOS).
 

sql/moz-fx-data-shared-prod/firefox_ios_derived/app_store_funnel_web_referrer_v1/query.sql

@@ -343,13 +343,13 @@ SELECT
     app_referrer_stats.deletions,
     source_type_stats.deletions,
     0
-  ) AS deletions,
+  ) AS opt_in_deletions,
   COALESCE(
     web_referrer_stats.installations,
     app_referrer_stats.installations,
     source_type_stats.installations,
     0
-  ) AS installations,
+  ) AS opt_in_installations,
   COALESCE(
     web_referrer_stats.sessions,
     app_referrer_stats.sessions,