In `design toolbox`, update wording key naming

[ludovic35]

Description

Demos content should use translated strings. As an example, button label should be translated when in Arabic or French.
To resume, we have:

non-translated strings for API parameters (string keys suffix is _tech)
translated strings for demo content and components illustrations (string keys suffix is _label)

Checklist for Core Team

• Documentations have been updated (if needed)
• Unit tests have been updated and still pass
• UI tests have been updated and still pass
• Retrocompatibility has been checked, or broken API have been flagged as deprecated with a workaround