PHP 8.1: Fix addslashes(): Passing null to parameter #1 () of type string is deprecated

[rebeccahum]

Deprecated: addslashes(): Passing null to parameter #1 ($string) of type string is deprecated in /wp/wp-content/mu-plugins/drop-ins/hyperdb/db.php on line 844 [es-site.vipdev.lndo.site/] [wp-content/mu-plugins/drop-ins/hyperdb/db.php:844 addslashes(), wp-includes/class-wpdb.php:1789 hyperdb->_real_escape(), wp-admin/includes/schema.php:1328 wpdb->prepare(), wp-admin/includes/schema.php:1040 populate_network_meta(), phar:///usr/local/binvendor/wp-cli/core-command/src/Core_Command.php:715 populate_network(), phar:///usr/local/binvendor/wp-cli/core-command/src/Core_Command.php:567 Core_Command->multisite_convert_(), Core_Command->multisite_install(), phar:///usr/local/binvendor/wp-cli/wp-cli/php/WP_CLI/Dispatcher/CommandFactory.php:100 call_user_func(), WP_CLI\Dispatcher\CommandFactory::WP_CLI\Dispatcher\{closure}(), phar:///usr/local/binvendor/wp-cli/wp-cli/php/WP_CLI/Dispatcher/Subcommand.php:491 call_user_func(), phar:///usr/local/binvendor/wp-cli/wp-cli/php/WP_CLI/Runner.php:431 WP_CLI\Dispatcher\Subcommand->invoke(), phar:///usr/local/binvendor/wp-cli/wp-cli/php/WP_CLI/Runner.php:454 WP_CLI\Runner->run_command(), phar:///usr/local/binvendor/wp-cli/wp-cli/php/WP_CLI/Runner.php:1269 WP_CLI\Runner->run_command_and_exit(), phar:///usr/local/binvendor/wp-cli/wp-cli/php/WP_CLI/Bootstrap/LaunchRunner.php:28 WP_CLI\Runner->start(), phar:///usr/local/binvendor/wp-cli/wp-cli/php/bootstrap.php:83 WP_CLI\Bootstrap\LaunchRunner->process(), phar:///usr/local/binvendor/wp-cli/wp-cli/php/wp-cli.php:32 WP_CLI\bootstrap(), phar:///usr/local/binphp/boot-phar.php:20 include('phar:///usr/local/binvendor/wp-cli/wp-cli/php/wp-cli.php'), /usr/local/bin/wp:4 include('phar:///usr/local/binphp/boot-phar.php')]