feat(atomic): integration of follow up ui in atomic generated answer

[mmitiche]

SFINT-6590

Summary

• The new follow up UI has been integrated in the atomic-generated-answer component.
• The new atomic-generated-answers-thread is now rendered when the follow up feature is enabled.
• The new ask follow up input is now rendered when the follow up feature is enabled.
• Added condition to disable ask follow up input when an answer generation is on going.
• When the follow ups feature is disabled, the component renders as usual, without the new thread component.

Note, this PR currently also contains changes from this PR: #7105 (review)

When follow ups are enabled

Screen.Recording.2026-02-26.at.7.42.01.AM.mov

When follow ups are disabled

Screen.Recording.2026-02-23.at.8.46.05.AM.mov