Log license fetch failures and surface honest warning toast on save

[TLabutis]

Summary

• When the Saferpay Management API license lookup fails on credentials save, log the error to the SaferPay module Logs tab via LoggerInterface instead of swallowing it silently
• Replace the misleading green success toast (which told merchants to "verify credentials" they had just validated) with an amber warning toast and a clearer message pointing to the Logs
• Return a warning flag from ajaxProcessSaveCredentials so the React layer can render the new variant

Test plan

• Force a license fetch exception → save credentials → amber warning toast renders with new copy
• Restore valid license fetch → save credentials → green success toast renders normally
• Verify the failure path writes an entry to the SaferPay module Logs tab (not the generic PrestaShop log)

[gemini-code-assist]

Code Review

This pull request enhances the credential saving process by implementing error handling for license retrieval failures. It introduces server-side logging for these errors and adds a new 'warning' toast variant to the frontend to inform users when settings are saved but license verification could not be completed. A review comment suggests refactoring the logging context to adhere to PSR-3 standards by removing a redundant 'context' key in the array.

[gemini-code-assist]

The LoggerInterface extends \Psr\Log\LoggerInterface, which follows the PSR-3 standard. In PSR-3, the second argument to logging methods is the context array itself. Wrapping the context data in a redundant 'context' key is unnecessary and may lead to nested structures in the log output (e.g., context.context.exception_class instead of context.exception_class).

                $logger->error('License fetch failed on credentials save: ' . $e->getMessage(), [
                    'exception_class' => get_class($e),
                ]);