Fix JSONB filter and admin guard

- Implement helper filter_jsonb_array_nulls and apply it in analyze_data_completeness to replace jsonb - 'null' usage
- Add search_path public in helper function for security
- Ensure useDataCompleteness runs only on admin pages by enabling query conditionally

supabase/migrations/20251112014542_0ab65adf-d76e-4a44-9695-35402dd46bcb.sql

@@ -0,0 +1,14 @@
+-- Fix search_path security issue for filter_jsonb_array_nulls function
+CREATE OR REPLACE FUNCTION filter_jsonb_array_nulls(arr JSONB)
+RETURNS JSONB
+LANGUAGE SQL
+IMMUTABLE
+SET search_path = public
+AS $$
+  SELECT COALESCE(
+    jsonb_agg(element),
+    '[]'::jsonb
+  )
+  FROM jsonb_array_elements_text(arr) element
+  WHERE element != 'null'
+$$;