[Security] Fixed XSS in class editor using date fields

[Corepex]

WHAT

🤖 Generated by Copilot at 5e83942

Fix date and datetime field validation and default value handling in object classes. Clear the field value if it is not a valid date object and prevent saving invalid dates. The changes affect the files date.js and datetime.js in the AdminBundle bundle.

🤖 Generated by Copilot at 5e83942

date field listens
clears invalid input now
autumn bug is fixed

HOW

🤖 Generated by Copilot at 5e83942

• Fix date field validation and default value handling for object classes (link, link)
  • Clear date field value if it is not a valid date object (link, link)
  • Check date field validity before formatting and setting default value (link)

[github-actions]

Review Checklist

• Target branch (10.5 for bug fixes, others 11.x)
• Bug fix: check if files are affected that were moved to a bundle - create a PR there if applicable
• Tests (if it's testable code, there should be a test for it - get help)
• Docs (every functionality needs to be documented, see here)
• Migration incl. install.sql (e.g. if the database schema changes, ...)
• Upgrade notes (deprecations, important information, migration hints, ...)
• Label
• Milestone