Use Rails' index_by where it makes sense (#15542)

* Use Rails' index_by where it makes sense

* Fix tests

Co-authored-by: Claire <claire.github-309c@sitedethib.com>

app/models/status.rb

@@ -301,7 +301,7 @@ class Status < ApplicationRecord
 
       return if account_ids.empty?
 
-      accounts = Account.where(id: account_ids).includes(:account_stat).each_with_object({}) { |a, h| h[a.id] = a }
+      accounts = Account.where(id: account_ids).includes(:account_stat).index_by(&:id)
 
       cached_items.each do |item|
         item.account = accounts[item.account_id]