Revert "Search: Fix only searching for folder id zero (#44175)" (#44424)

This reverts commit 007cd144a9 from #44175.

pkg/services/sqlstore/searchstore/filters.go

@@ -87,16 +87,10 @@ func (f TitleFilter) Where() (string, []interface{}) {
 }
 
 type FolderFilter struct {
-	Dialect migrator.Dialect
-	IDs     []int64
+	IDs []int64
 }
 
 func (f FolderFilter) Where() (string, []interface{}) {
-	if len(f.IDs) == 1 && f.IDs[0] == 0 {
-		sql := fmt.Sprintf("dashboard.folder_id = 0 AND dashboard.is_folder = %s", f.Dialect.BooleanStr(false))
-		return sql, []interface{}{}
-	}
-
 	return sqlIDin("dashboard.folder_id", f.IDs)
 }