Validation when posting packages and tickets doesn't check if person or location exists for CreatedByPersonID or CreatedAtLocationID

Issue in PackageController.cs

calls:
PostPackage(PackageRequestModel request)
request:
{
"sender": "string",
"receiverId": "string",
"name": "string",
"collectionPointId": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
"createdByPersonId": "some invalid ID",
"createdAtLocationId": "some invalid ID"
}

PostTicket(TicketRequestModel request)
request:
{
"locationId": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
"completedByPersonId": "1",
"packageId": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
"receivedByPersonId": "some invalid id"
}

should be:
validation error

actual:
call goes through as normal despite the invalid ID in the request

quality tip:
check through the validation methods in the packagecontroller and see how you can make the error handling more verbose and worded correctly.