Fix after_change callback for unique_list

[vsmay98]

Fix: #64

This fix will support after_change callback for unique_list

class Person < ApplicationRecord
  kredis_list :names, after_change: ->(p) {  }
  kredis_unique_list :skills, limit: 2, after_change: :skillset_changed

  def skillset_changed
    puts 'skillset_changed'
  end
end

Loading development environment (Rails 7.0.0)
3.0.0 :001 > Person.last.skills << 'rails'
  Person Load (0.2ms)  SELECT "persons".* FROM "persons" ORDER BY "persons"."id" DESC LIMIT ?  [["LIMIT", 1]]
  Kredis Proxy (0.0ms)  LREM persons:2:skills [0, "rails"]
  Kredis Proxy (0.0ms)  RPUSH persons:2:skills ["rails"]
  Kredis Proxy (0.0ms)  LTRIM persons:2:skills [-5, -1]
skillset_changed
 => [0, 2, "OK"]

[vsmay98]

Hello @julianrubisch @dhh,
Could you please review this PR?