webui: Add a "Continue" Action for Assistant Message (#16971)
* feat: Add "Continue" action for assistant messages
* feat: Continuation logic & prompt improvements
* chore: update webui build output
* feat: Improve logic for continuing the assistant message
* chore: update webui build output
* chore: Linting
* chore: update webui build output
* fix: Remove synthetic prompt logic, use the prefill feature by sending the conversation payload ending with assistant message
* chore: update webui build output
* feat: Enable "Continue" button based on config & non-reasoning model type
* chore: update webui build output
* chore: Update packages with `npm audit fix`
* fix: Remove redundant error
* chore: update webui build output
* chore: Update `.gitignore`
* fix: Add missing change
* feat: Add auto-resizing for Edit Assistant/User Message textareas
* chore: update webui build output
