Tutorial free period management: date validation is unintuitive when editing an existing tutorial free period

[hanna20022005]

Describe the bug

When one edits the reason through the editing window, the date keeps its red frame implying one's input is invalid even though it is valid and will submit just fine when one tries to submit the form.

To Reproduce

1. Go to tutorial management in a course you have the necessary permissions in
2. Click on holidays and create a new free period without a reason
3. hover to the right of the table to click on the edit button
4. enter a reason but keep the date unchanged
5. see red frame around date, still try submitting
6. submit goes through

Expected behavior

the date should not have a red frame if it is valid input (-> remove the frame if a change is detected in the reasons box?)

Screenshots

2026-01-28.10-22-39.mp4

Which version of Artemis are you seeing the problem on?

8.8.0

What browsers are you seeing the problem on?

Microsoft Edge

Additional context

No response

Relevant log output