Display fixes for weekly analytics emails

[epipav]

What

🤖 Generated by Copilot at 8702d75

The pull request improves the weekly analytics email feature by using a service class to format the activity descriptions and by shortening the email content. It also fixes a potential bug in the ActivityDisplayService class by adding a condition to check for the presence of activity attributes.
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🤖 Generated by Copilot at 8702d75

We are the masters of display
We control the icons and the colors
We summon the attributes of the activity
Or we cast them into the void

Why

How

🤖 Generated by Copilot at 8702d75

• Replace prettyActivityTypes object with ActivityDisplayService class to provide more flexible and consistent display options for activity types in weekly analytics email (link, link, link, link)
• Reduce the limit of top conversation starters for each segment from 5 to 3 in weeklyAnalyticsEmailsWorker.ts to make the email more concise and focused (link)
• Add condition to check if activity has attributes in ActivityDisplayService.getDisplayOptions method to prevent errors (link)

Checklist ✅

• Label appropriately with Feature, Improvement, or Bug.
• Add screehshots to the PR description for relevant FE changes
• New backend functionality has been unit-tested.
• API documentation has been updated (if necessary) (see docs on API documentation).
• Quality standards are met.