MSD: Hide callout image on mobile.

[StevenDufresne]

Related to: #107119
Part of DOTMSD-849, DES-52

Proposed Changes

This PR hides the callout images when on mobile devices.

@p-jackson Led some discussion in #103414 to agree on a mobile approach but no resolution was made. He did suggest hiding the images but noted that its underwhelming.

Since these modals are in production, I think it's wise for us to hide them. The experience is not great in the V1 dashboard as it is. Hiding the image, while underwhelming make the callout more useable while giving us time to align on best approach.

Screenshot

Before	After

Responsive

Why are these changes being made?

Testing Instructions

Pre-merge Checklist

• Has the general commit checklist been followed? (PCYsg-hS-p2)
• Have you written new tests for your changes?
• Have you tested the feature in Simple (P9HQHe-k8-p2), Atomic (P9HQHe-jW-p2), and self-hosted Jetpack sites (PCYsg-g6b-p2)?
• Have you checked for TypeScript, React or other console errors?
• Have you tested accessibility for your changes? Ensure the feature remains usable with various user agents (e.g., browsers), interfaces (e.g., keyboard navigation), and assistive technologies (e.g., screen readers) (PCYsg-S3g-p2).
• Have you used memoizing on expensive computations? More info in Memoizing with create-selector and Using memoizing selectors and Our Approach to Data
• Have we added the "[Status] String Freeze" label as soon as any new strings were ready for translation (p4TIVU-5Jq-p2)?
  • For UI changes, have we tested the change in various languages (for example, ES, PT, FR, or DE)? The length of text and words vary significantly between languages.
• For changes affecting Jetpack: Have we added the "[Status] Needs Privacy Updates" label if this pull request changes what data or activity we track or use (p4TIVU-aUh-p2)?

[github-actions]

Calypso Live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-162050

Jetpack Cloud live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-162050&env=jetpack

Automattic for Agencies live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-162050&env=a8c-for-agencies

[fushar]

Nice. Agree with this solution.