fix(ft): fix default ft config

apps/emqx_ft/etc/emqx_ft.conf

@@ -4,7 +4,7 @@ file_transfer {
         segments {
             root = "{{ platform_data_dir }}/file_transfer/segments"
             gc {
-                interval = 60000
+                interval = "1h"
             }
         }
         exporter {