Exclude additional meta keys from the meta export

Use the woocommerce_bookings_export_skip_meta_keys filter when the custom meta export should omit plugin-owned or internal fields. Core booking data-store keys, _edit_lock, and _edit_last are already excluded. The snippet below adds another private meta key to the skipped list for confirmed bookings and returns a de-duplicated key list.

add_filter(
	'woocommerce_bookings_export_skip_meta_keys',
	function ( array $keys, WC_Booking $booking ): array {
		if ( 'confirmed' === $booking->get_status() ) {
			$keys[] = '_my_plugin_internal_key';
		}

		return array_unique( $keys );
	},
	10,
	2
);