fix: resolve erroneous types and classes in phpstan baseline

This commit resolves multiple issues identified by the phpstan static analysis tool. The erroneous
types and classes in `AbstractShippingEntry.php`, `EventHandler.php`, `ShippingTimePeriod.php` have
been refractored to match the correct class and method signatures. The erroneous sections have been
updated with the appropriate classes and methods for QUI\\\\ERP\\\\Accounting\\\\Invoice,
QUI\\\\ERP\\\\Accounting\\\\Offers, and QUI\\\\ERP\\\\SalesOrders.

Related: #55