feat(admin): expose last_login_at on players and add column to admin UI

Fixing the admin panel audit logs 500 error and adding last login visibility for user engagement tracking

Author: Bulletdev

app/modules/players/serializers/player_serializer.rb

@@ -15,7 +15,7 @@ class PlayerSerializer < Blueprinter::Base
          :riot_puuid, :riot_summoner_id, :profile_icon_id,
          :twitter_handle, :twitch_channel, :instagram_handle,
          :kick_url, :professional_name,
-         :notes, :sync_status, :last_sync_at, :created_at, :updated_at,
+         :notes, :sync_status, :last_sync_at, :last_login_at, :created_at, :updated_at,
          :player_access_enabled, :player_email, :deleted_at, :removed_reason
 
   field :age do |obj|