extract public to schema variable so we can use a constant later

pg4wp/rewriters/SelectSQLRewriter.php

@@ -358,7 +358,7 @@ class SelectSQLRewriter extends AbstractSQLRewriter
     }
 
     // This method is specifically to handle should_suggest_persistent_object_cache in wp site health
-    protected function postgresTableSizeRewrite() 
+    protected function postgresTableSizeRewrite($schema = 'public') 
     {
 
         $sql = <<<SQL
@@ -373,7 +373,7 @@ class SelectSQLRewriter extends AbstractSQLRewriter
         INNER JOIN 
             pg_stat_user_tables S ON (S.relid = C.oid) 
         WHERE 
-            N.nspname = 'public' AND 
+            N.nspname = $schema AND 
             C.relname IN ('wp_comments','wp_options','wp_posts','wp_terms','wp_users')
         GROUP BY 
             C.relname, pg_total_relation_size(C.oid), S.n_live_tup;