WPForms PayPal Standard Addon 1.10.0

### Changed
- Improved field layout on the frontend for better user experience on mobile devices.

### Fixed
- Improved handling of corrupted payment submission data.
- In some cases, payments couldn't be submitted due to expired tokens.

### IMPORTANT
- Support for PHP 5.6 has been discontinued. If you are running PHP 5.6, you MUST upgrade PHP before installing WPForms PayPal Standard 1.9.0. Failure to do that will disable WPForms PayPal Standard functionality.
- Support for WordPress 5.4 and below has been discontinued. If you are running any of those outdated versions, you MUST upgrade WordPress before installing WPForms PayPal Standard 1.9.0. Failure to do that will disable WPForms PayPal Standard functionality.

### Changed
- Minimum WPForms version supported is 1.8.4.

### Fixed
- Statuses of refunded payments were not correctly mirrored on the Payments Overview and Single Payment pages.
- Error messages were duplicated when there was no payment field.

### Changed
- Minimum WPForms version supported is 1.8.3.