Refactor Self-Hosted Duo Frontend to Use Shared Feature Settings Components

Description

Self-hosted Duo and Model Selection should share common components for rendering feature settings. Refactor Self-Hosted Duo feature settings to use components in ee/app/assets/javascripts/ai/shared/feature_settings/ instead.

Context

Instead of refactoring existing Self-hosted Duo components to make them re-usable for model selection, a choice was made to flip this and duplicate the components for model selection first and later refactor these for shared use with self-hosted Duo. This created tech debt but also enabled faster delivery of model selection (table stakes) and eliminated potential regressions with self-hosted Duo during testing.

Definition of Done:

• ee/app/assets/javascripts/ai/duo_self_hosted/ code paths uses shared ee/app/assets/javascripts/ai/shared/feature_settings/ components

• ee/app/assets/javascripts/ai/duo_self_hosted/ feature settings non-shared components are deleted once the switchover above is complete.