[core] Update Tidelift reference

[oliviertassinari]

I'm hunting all MUI references, to remove them. On the sponsor button, we have

which we can replace with:

index f3791ee9..7c31ebdb 100644
--- a/.github/FUNDING.yml
+++ b/.github/FUNDING.yml
@@ -4,5 +4,5 @@ github: # Replace with up to 4 GitHub Sponsors-enabled usernames e.g., [user1, u
 patreon: # Replace with a single Patreon username
 open_collective: mui-org
 ko_fi: # Replace with a single Ko-fi username
-tidelift: npm/@mui/material
+tidelift: npm/@base-ui-components/react
 custom: # Replace with a single custom sponsorship URL

once we published #805.