bug: Unable to *not* send optional fields through UI

[wasnertobias]

Describe the bug

If a string field of a flow input is not required, but if it is given, it is validated based on some logic in our case: So it makes a huge difference if the field is set, but an empty value is given or if the field is not set => None value.

Through the UI, if no value is given for a string value, it falls back to setting the field with an empty string value, which causes a validation error in our case. Because of that, we have to use the REST interface and Postman for testing any requests.

To reproduce

Flow input with an optional string field.

Expected behavior

Give me the possibility to "remove" the field, if it is not required.
Or: Give me the possibility to edit raw JSON data.

Screenshots

No response

Browser information

Chrome 124.0.6367.119

Application version

EE v1.323.6-9-g1795522d2

Additional Context

No response

[fatonramadani]

A field can now be "nullable": If enabled, the default value will be null and not an empty string.