Commit fb4fe3004 restored the previous behaviour to check the company_id in case of FullMultipleCompanySupport.
But after rereading the code and the laravel documentation, the check is already there where it belongs in AssetStoreRequest::prepareForValidation()
The bug is the is_int-check of the request input in prepareForValidation(). Is is of type string even if it is a numeric value, so the call to getIdForCurrentUser() never happend.
Fix this by removing the check and the now redundant call to getIdForCurrentUser().
Wrong values will get caught by the model-level validation rules.
f3c4e55667