NIFI-15978: Rendering allowable value descriptions in the Connector w…

[mcgilman]

…izard.

NIFI-15978 Rendering allowable value descriptions in the Connector wizard

Summary

The Connector wizard's property dropdowns currently render only an allowable value's display name, even though the framework's AllowableValueDTO already serializes a description field (used elsewhere — e.g. processor property dialogs — to give users context about each option). This PR plumbs that description through to the wizard's searchable-select so users see the same secondary descriptive text per option that they see in the rest of the UI.

Changes

• libs/shared/src/types/index.ts — Added the optional description?: string to the nested AllowableValue.allowableValue shape so it matches what the backend already returns from AllowableValueDTO.
• libs/shared/src/components/connector-property-input/connector-property-input.component.ts — In computeSelectOptions, propagate av.allowableValue.description onto the emitted SearchableSelectOption. The searchable-select component already renders an option's description as a secondary line (and already sizes virtual-scroll rows accordingly), so no template or styling changes are needed.
• libs/shared/src/components/connector-property-input/connector-property-input.component.spec.ts — Extended the makeAllowable helper to accept an optional description, adjusted existing assertions to expect description: undefined where appropriate, and added focused specs covering description propagation for both the static property.allowableValues path and the dynamic PropertyAllowableValuesState path.

Backend alignment

No backend changes are required. Verified that:

• AllowableValueDTO already exposes description (getDescription() / setDescription()).
• DtoFactory.createAllowableValueDto(...) populates the description for statically declared allowable values.
• StandardNiFiServiceFacade populates the description for allowable values produced dynamically via a property's AllowableValuesProvider.

So any connector that declares descriptions on its AllowableValues — static or dynamic — will surface them in the wizard with no further wiring.

[scottyaslan]

Reviewing...