Fix startDate and endDate not prefilled in Update Listing page

Description: In the file gallery/src/pages/UpdateListing.jsx, when updating a listing, all details are correctly fetched and displayed except for the startDate and endDate fields. These values are not being populated automatically from the existing listing data, forcing the user to manually re-enter them before submitting the update form.

Steps to Reproduce:

1. Go to the Profile page.
2. Open an existing listing for editing, if there is none create one listing first.
3. Observe that startDate and endDate are not prefilled.

Expected Behavior: Both startDate and endDate should be fetched and displayed automatically like the other fields when updating a listing.