Remove `max_toot_chars` from initial-state

This is still in `/api/v1/instance` for compatibility with other clients

app/serializers/initial_state_serializer.rb

@@ -5,7 +5,7 @@ class InitialStateSerializer < ActiveModel::Serializer
 
   attributes :meta, :compose, :accounts,
              :media_attachments, :settings,
-             :max_toot_chars, :max_feed_hashtags, :poll_limits,
+             :max_feed_hashtags, :poll_limits,
              :languages
 
   attribute :critical_updates_pending, if: -> { object&.role&.can?(:view_devops) && SoftwareUpdate.check_enabled? }
@@ -13,10 +13,6 @@ class InitialStateSerializer < ActiveModel::Serializer
   has_one :push_subscription, serializer: REST::WebPushSubscriptionSerializer
   has_one :role, serializer: REST::RoleSerializer
 
-  def max_toot_chars
-    StatusLengthValidator::MAX_CHARS
-  end
-
   def max_feed_hashtags
     TagFeed::LIMIT_PER_MODE
   end