Revert "Replace desktop watchstar icon with mobile skin one"
Based on the discussion on T56307, this change is controversial
and not necessarily wanted. In summary:
- Green star looks out of place with blue Vector (Edokter, Esanders, Trevor)
- Clashes with WikiLove heart icon (Edokter)
- Flat design doesn't fit with Vector's gradient style (Rillke)
- Green means constructive in MediaWiki UI, however clicking the green star removes a page from your watchlist (Krinkle)
This reverts commit 56825d209e5c87a23e30a7aa3cb57b5a731ec2be.