Remove unused require of "active_support/deprecation" in DBconsoleCommand

In 7a26f26 the usage of
`ActiveSupport::Deprecation.warn` in `DBconsoleCommand` was replaced with
`Rails.deprecator.warn`, which is already required by Rails::Command.

Author: p8

railties/lib/rails/commands/dbconsole/dbconsole_command.rb

@@ -1,7 +1,6 @@
 # frozen_string_literal: true
 
 require "active_support/core_ext/string/filters"
-require "active_support/deprecation"
 require "rails/command/environment_argument"
 
 module Rails