Add Enter key support to StudioToggleableTextfield

[coderabbitai]

Current Behavior

When using the StudioToggleableTextfield component, pressing the Enter key does not save the changes and unfocus the field.

Expected Behavior

The component should save the changes and unfocus (exit edit mode) when the user presses the Enter key, similar to how most text input fields behave.

Context

This improvement would enhance the user experience by providing a more intuitive way to complete text editing.
Identified in PR discussion: #14400