Refactor key access and role warning in Supabase clients

The update simplifies accessing environment keys and role warnings in Supabase clients by moving them to new functions 'getSupabaseClientKeys' and 'getServiceRoleKey'. The redundancy in the code is reduced promoting clearer and more maintainable code. The '@epic-web/invariant' import has been removed from files as it is no longer needed.

apps/web/package.json

@@ -29,7 +29,6 @@
     "supabase:typegen:app": "supabase gen types typescript --local > ./lib/database.types.ts"
   },
   "dependencies": {
-    "@epic-web/invariant": "^1.0.0",
     "@hookform/resolvers": "^3.3.4",
     "@kit/accounts": "workspace:^",
     "@kit/admin": "workspace:^",