Fix 'bighits' vs 'big_hits'

## Issue
- #6840 Clean up https://odysee.com/$/big_hits
- `/big_hits` is being indexed and unnecessarily affecting the speed score (the "not found" page is surprisingly slow; will handle separately)
- Big-Hits metadata not working

## Notes
'big_hits' is only used in v1 homepages.

ui/constants/pages.js

@@ -7,7 +7,7 @@ exports.AUTH_WALLET_PASSWORD = 'walletpassword';
 exports.BACKUP = 'backup';
 exports.CHANNEL = 'channel';
 exports.DISCOVER = 'discover';
-exports.BIG_HITS = 'big_hits';
+exports.BIG_HITS = 'bighits';
 exports.MOVIES = 'movies';
 exports.MUSIC = 'music';
 exports.COMMUNITY = 'community';