Description

In the Inspector panel, under the Record Summary section, when configuring custom fields, the dropdown for selecting fields was displaying a blank/empty selectable option. This caused confusion for users, as standard dropdowns should contain clearly labeled field names.

Expected behavior

When clicking the "Customize Fields" dropdown in the Record Summary section, the dropdown should display:

"None" as a clear placeholder option (when no field is selected)
A list of available columns/fields from the table
Instead of showing a blank, unlabeled entry.

To Reproduce

1.Open a Table in Mathesar
2.Open the Inspector panel (usually on the right side)
3.Navigate to the Record Summary section
4.Click on the "Customize Fields" dropdown
5.Before fix: The dropdown showed one empty/blank entry with no label
6.After fix: The dropdown now shows "None" as a clear placeholder

Environment

• Mathesar version: 0.8.0+
• Browser: All modern browsers (Chrome, Firefox, Safari, Edge)
• Component Affected: Record Summary Inspector

Additional context