Catch WC_Data_Exception to avoid black screen

Also incldued a check to avoid duplicated messages about invalid billing
address emails.

includes/class-wc-form-handler.php

@@ -149,12 +149,19 @@ class WC_Form_Handler {
 				}
 			}
 
+			try {
 				// Set prop in customer object.
 				if ( is_callable( array( $customer, "set_$key" ) ) ) {
 					$customer->{"set_$key"}( $value );
 				} else {
 					$customer->update_meta_data( $key, $value );
 				}
+			} catch ( WC_Data_Exception $e ) {
+				// Set notices. Ignore invalid billing email, since is already validated.
+				if ( 'customer_invalid_billing_email' !== $e->getErrorCode() ) {
+					wc_add_notice( $e->getMessage(), 'error' );
+				}
+			}
 		}
 
 		/**