Email Validation Not Working

[ytausch]

Currently, OapiRequestValidator from oapi-codegen seems not to be able to filter syntactically invalid emails in incoming requests.

This is very likely an upstream issue, however, the details of the issue must be investigated.

The corresponding API tests that are failing were disabled and can be enabled again to reproduce this issue.

These are the failing tests:

• TestCreateRental_invalidCustomerId
• TestGetRentalOverview_invalidCustomerId
• TestSetLockState_customerId_invalidCustomerId