20220921 fix 後台匯出功能

app/Http/Services/Backend/DataManagement/SignupManagementService.php

             ->select('*');
             
         if ($keyword) {
-            $res->where(function($q) use ($keyword) {
+            $res = $res->where(function($q) use ($keyword) {
                 $q->where('firstName', $keyword)
                     ->orWhere('lastName', $keyword)
                     ->orWhere('companyName', $keyword)