1. Install the PayPal Checkout gateway
2. Submit the "Update Settings" button without entering any details
3. A white page is encountered. The following error is written to logs:

==> general-warning-2023-08-07.log <==
[2023-08-07T18:43:55.227988+00:00] general.WARNING: E_WARNING: Undefined array key "sandbox"

[2023-08-07T18:43:55.577790+00:00] general.WARNING: E_WARNING: Undefined property: stdClass::$name

==> general-error-2023-08-07.log <==
[2023-08-07T18:43:55.579230+00:00] general.ERROR: Exception: It was not possible to authenticate to the API. Verify that the credentials are correct. in /home/blestau/public_html/580b1/components/gateways/nonmerchant/paypal_checkout/lib/paypal_checkout_api.php:90 Stack trace: #0 /home/blestau/public_html/580b1/components/gateways/nonmerchant/paypal_checkout/lib/paypal_checkout_api.php(65): PaypalCheckoutApi->authenticate() #1 /home/blestau/public_html/580b1/components/gateways/nonmerchant/paypal_checkout/paypal_checkout.php(560): PaypalCheckoutApi->__construct() #2 /home/blestau/public_html/580b1/components/gateways/nonmerchant/paypal_checkout/paypal_checkout.php(574): PaypalCheckout->getApi() #3 [internal function]: PaypalCheckout->validateConnection() #4 /home/blestau/public_html/580b1/vendors/minphp/input/src/Input.php(546): call_user_func_array() #5 /home/blestau/public_html/580b1/vendors/minphp/input/src/Input.php(367): Minphp\Input\Input->validateRule() #6 /home/blestau/public_html/580b1/components/gateways/nonmerchant/paypal_checkout/paypal_checkout.php(103): Minphp\Input\Input->validates() #7 /home/blestau/public_html/580b1/app/models/gateway_manager.php(437): PaypalCheckout->editSettings() #8 /home/blestau/public_html/580b1/app/controllers/admin_company_gateways.php(119): GatewayManager->edit() #9 /home/blestau/public_html/580b1/vendors/minphp/bridge/src/Lib/Dispatcher.php(142): AdminCompanyGateways->manage() #10 /home/blestau/public_html/580b1/index.php(21): Dispatcher::dispatch() #11

We shouldn't encounter an exception. Are we not validating fields well enough before submitting them? A visible error should be shown if the details are clearly incorrect, rather than an exception.