Portal: KeyValueMapField should not emit hidden input when empty

[alexluong]

Problem

KeyValueMapField always renders a hidden <input> with JSON.stringify() of its pairs. When there are no valid key-value pairs, this produces "{}" (empty JSON object), which the webhook destination backend validation rejects — it expects either a non-empty headers map or the field to be absent/empty string.

Currently both CreateDestination and DestinationSettings have band-aid fixes that convert "{}" to "" for custom_headers specifically. This is fragile and requires every consumer to handle the edge case.

Proposed fix

Fix KeyValueMapField at the source: don't render the hidden <input> when there are no valid pairs. This way the field is simply absent from the form data — no ambiguity between "" and "{}", and no band-aids needed in consumers.

Once the component is fixed, remove the custom_headers workarounds in:

• CreateDestination.tsx
• DestinationSettings.tsx

Files

• internal/portal/src/common/KeyValueMapField/KeyValueMapField.tsx
• internal/portal/src/scenes/CreateDestination/CreateDestination.tsx
• internal/portal/src/scenes/Destination/DestinationSettings/DestinationSettings.tsx

[alexluong]

ignore, not the right ticket, i was brainstorming with Claude and they went slightly ahead of the plan 😬