dev #72825 fix failures

library/Class/Profil/Preferences/LoansHistory.php

@@ -26,7 +26,7 @@ class Class_Profil_Preferences_LoansHistory extends Class_Profil_Preferences_Loa
     $conf = $profile->getCfgModulesPreferences('abonne', 'loans-history', '');
     $table_composition = isset($conf['table_composition'])
       ? $conf['table_composition']
-      : '';
+      : null;
 
     return $this->getTableComposition($table_composition);
   }

library/Class/Profil/Preferences/LoansPNB.php

@@ -26,7 +26,7 @@ class Class_Profil_Preferences_LoansPNB extends Class_Profil_Preferences_Loans{
     $conf = $profile->getCfgModulesPreferences('abonne', 'prets', '');
     $table_composition = isset($conf['pnb_table_composition'])
       ? $conf['pnb_table_composition']
-      : '';
+      : null;
 
     return $this->getTableComposition($table_composition);
   }