Fix/31582 special characters in password on checkout page lead to not working account (#43777)

* Fix registration during checkout

* Added changelog.

* Moved changelog.

* Added correct spacing

* Move password slashing into WC_Checkout:get_posted_data()

* Lint fix

plugins/woocommerce/changelog/31582-special-characters-in-password-on-checkout-page-lead-to-not-working-account

@@ -0,0 +1,4 @@
+Significance: minor
+Type: fix
+
+Fixed a bug affecting registration during checkout that would prevent a new user from logging in.

plugins/woocommerce/includes/class-wc-checkout.php

@@ -783,6 +783,9 @@ class WC_Checkout {
 							$value = wc_sanitize_textarea( $value );
 							break;
 						case 'password':
+							if ( $data['createaccount'] && 'account_password' === $key ) {
+								$value = wp_slash( $value ); // Passwords are encrypted with slashes on account creation, so we need to slash here too.
+							}
 							break;
 						default:
 							$value = wc_clean( $value );