refactor: simplify region creation and update code attribute

- Change from find_or_initialize_by to find_or_create_by for
  regions.
- Set region code to the name instead of nil.

This refactor reduces complexity in how regions are created and
ensures the code attribute is properly populated with the
region's name, enhancing data consistency.

lib/tasks/sync_geo_data.rake

@@ -22,14 +22,12 @@ namespace :geo do
     count = 1
 
     regions.each do |data|
-      region = Region.find_or_initialize_by(name: data["name"]) do |r|
-      end
+      region = Region.find_or_create_by(name: data["name"])
       puts "Sync Regions[#{count}/#{sum}]: [#{region.name}]"
       count += 1
 
       region.update(
-        name: data["name"],
-        code: nil,
+        code: data["name"],
         translations: data["translations"],
         flag: data["flag"] || true,
         wiki_data_id: data["wikiDataId"]