Remove unused E2EE messaging code (#31193)

db/migrate/20240720140205_drop_end_to_end_message_tables.rb

@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+class DropEndToEndMessageTables < ActiveRecord::Migration[7.1]
+  def up
+    drop_table :system_keys
+    drop_table :one_time_keys
+    drop_table :encrypted_messages
+    drop_table :devices
+    safety_assured { remove_column :accounts, :devices_url }
+  end
+
+  def down
+    raise ActiveRecord::IrreversibleMigration
+  end
+end