DEV: Refactor DiscourseAutomation::DestroyAutomation a bit

Small followup to 932bd6b.

plugins/automation/app/services/discourse_automation/destroy.rb

@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+class DiscourseAutomation::Destroy
+  include Service::Base
+
+  # @!method self.call(guardian:, params:)
+  #   @param [Guardian] guardian
+  #   @param [Hash] params
+  #   @option params [Integer] :automation_id
+  #   @return [Service::Base::Context]
+
+  policy :can_destroy_automation
+
+  params do
+    attribute :automation_id, :integer
+    validates :automation_id, presence: true
+  end
+
+  model :automation
+
+  transaction do
+    step :log_action
+    step :destroy_automation
+  end
+
+  private
+
+  def can_destroy_automation(guardian:)
+    guardian.is_admin?
+  end
+
+  def fetch_automation(params:)
+    DiscourseAutomation::Automation.find_by(id: params.automation_id)
+  end
+
+  def log_action(automation:, guardian:)
+    StaffActionLogger.new(guardian.user).log_custom(
+      "delete_automation",
+      **automation.slice(:id, :name, :script, :trigger),
+    )
+  end
+
+  def destroy_automation(automation:)
+    automation.destroy!
+  end
+end