AI Assistant: Add disclaimer to image generation input (#40397)

* refactor from first proposal

* change guideline links to jetpack redirect

* add disclaimer to image modals

* add AiModalFooter component

* use AiModalFooter component on images modal

* use AiModalFooter component on logo generator modal

* changelog

* remove arrow icon and use character instead

Committed via a GitHub action: https://github.com/Automattic/jetpack/actions/runs/12166781596

Upstream-Ref: Automattic/jetpack@4ce0e2b