fix(phpstan): ensure compatibility with different datatypes

This commit ensures compatibility with different datatypes by adding necessary checks and type
conversions in ERP Products module. It also removes unused comments, thus making the code cleaner
and more efficient.

Changes include:
- In methods expecting integer parameters, explicit type casting has been added to situations where
a string could be passed instead.
- Additional checks are implemented before invoking method_exists(), ensuring safety.
- Inappropriate comments and annotations have been removed to make the code more readable.
- getEditableFieldIdsForProduct() and getInheritedFieldIdsForProduct() methods in Products.php had
a generic parameter $Product, it has been type hinted with the ProductTypeInterface.

Overall, the changes ensure better type stability and increase code reliability.

Related: #397