[Manifest validation] Ensure screenshot metadata is validated following Richer Install UI Recomendation

[nmetulev]

Tell us about your feature idea

Our validation library should validate the screenshot metadata based on the latest recommendations for screenshots as described here: https://web.dev/patterns/advanced-apps/richer-install-ui/

Do you have an implementation or a solution in mind?

• [ ] #4030
• [ ] #4031
• [ ] #4032

Have you considered any alternatives?

No response

[ghost]

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