🐞[BUG] Misleading timezone conversion during policy creation

[ds-crehm]

Description

Happened during testing of #639 on E2E and Dev/Test:
The timezone used for the validUntil date when creating policies is unclear to the user. The date is shown differently in different instances.

Current behaviour

When creating policies from the frontend, one can only input a validUntil time that is in the future. The timezone checked for is the local time.

After creating the policy with a valid timestamp, it is shown with the same timestamp in the detail view:

But in the table view, it is shown in a different timezone:

In the backend it is stored like that as well:

1720535580 converted is 09.07.2024 16:33:00
(But the validUntil date above is the 'correct' one)

When creating policies from the backend, the verification happens with the different timezone, which means I can effectively create policies that are already expired. This should not be possible.

Backend:
Validation works:

Validation does not work for policies <2 hours in the past:

Frontend detail view:

Expected behavior

The validUntil time is always in the timezone of the current user. There is no conversion to a different timezone, as this will only cause confusion.

Steps to reproduce the Bug

1. Log in as admin
2. Create policy with validUntil timestamp
3. Look at validUntil timestamp in the detail view and compare it to the validUntil timestamp in the table view

Alternatively:

1. Create policy in the backend with validUntil timestamp <2 hours in the past
2. Policy will be created
3. Look at policy in frontend and compare validUntil timestamps