fix(progress): drop bogus tenant_id filter on lesson_completions in student dashboard

lesson_completions has no tenant_id column — same root cause as 264f406.
The standalone query for the dashboard stat was still filtering by it,
returning 0 rows and showing "0 lessons completed" permanently.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: guillermoscript

app/[locale]/dashboard/student/page.tsx

@@ -47,8 +47,7 @@ async function getData(userId: string, tenantId: string) {
     supabase
       .from('lesson_completions')
       .select('lesson_id')
-      .eq('user_id', userId)
-      .eq('tenant_id', tenantId),
+      .eq('user_id', userId),
 
     supabase
       .from('exams')