Add guidance to release post for screenshots

Why is this change being made?

Historically many screenshots in our release post say "Test", "Demo", "example" and have other testing data like local domain names.

We can improve the screenshots by including realistic user-like data that illustrates how a feature works in a real production-like environment instead of in a demo environment.

Author Checklist

• Provided a concise title for the MR
• Added a description to this MR explaining the reasons for the proposed change, per say-why-not-just-what
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