Unconditionally use get_current_network_id (#329)

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Author: swissspidy

src/Core_Command.php

@@ -1559,16 +1559,9 @@ public function update_db( $args, $assoc_args ) {
 
 		if ( $network ) {
 			// Determine the network ID to update.
-			// get_current_network_id() (available since WP 4.9) reflects the network
-			// determined from the --url context, enabling per-network updates in
-			// multinetwork setups. Fall back to SITE_ID_CURRENT_SITE for older WordPress.
-			if ( function_exists( 'get_current_network_id' ) ) {
-				$network_id = get_current_network_id();
-			} elseif ( defined( 'SITE_ID_CURRENT_SITE' ) ) {
-				$network_id = (int) SITE_ID_CURRENT_SITE;
-			} else {
-				$network_id = 1;
-			}
+			// get_current_network_id() reflects the network determined from the --url context,
+			// enabling per-network updates in multinetwork setups.
+			$network_id = get_current_network_id();
 
 			$iterator_args = [
 				'table' => $wpdb->blogs,