Fix i18n induced issues with learning activity icons.

[rtibbles]

Summary

Description of the change(s) you made

• Update tree view to include new metadata #3344 inadvertently used translated strings to select the appropriate learning activity icon
• This went undetected until we actually had translations in place, so for non-English languages this broke
• This fixes this by removing the translation step from the icon selection

Manual verification steps performed

1. Switch to a non-English interface language
2. Look at the tree view for items with learning activities assigned
3. See them displayed properly

Updated behaviour to fix automated tests also.

Screenshots (if applicable)

References

Fixes#3748

[bjester]

Looks good

[radinamatic]

Is this deployed to hotfixes Studio already? Because I'm not seeing any change when browsing in non English UI... 😕

Cleared cache and all site data, but no dice.

learning-activity-icons.mp4

[bjester]

@radinamatic Looks like the build failed. I've restarted it

[radinamatic]

Icons are back in non-English Studio UI! 🎉 🎉 🎉 🎉 🎉