Apply Rubocop Style/RedundantAssignment (#23452)

app/models/concerns/omniauthable.rb

@@ -97,8 +97,7 @@ module Omniauthable
     def ensure_valid_username(starting_username)
       starting_username = starting_username.split('@')[0]
       temp_username = starting_username.gsub(/[^a-z0-9_]+/i, '')
-      validated_username = temp_username.truncate(30, omission: '')
-      validated_username
+      temp_username.truncate(30, omission: '')
     end
   end
 end

app/models/setting.rb

@@ -23,7 +23,7 @@ class Setting < RailsSettings::Base
     def [](key)
       return super(key) unless rails_initialized?
 
-      val = Rails.cache.fetch(cache_key(key, nil)) do
+      Rails.cache.fetch(cache_key(key, nil)) do
         db_val = object(key)
 
         if db_val
@@ -35,7 +35,6 @@ class Setting < RailsSettings::Base
           default_settings[key]
         end
       end
-      val
     end
 
     def all_as_records