Currently, manually created backups contain list of categories even if
Categories option is not selected during Backup Prompt. This leads to
empty categories being created when restoring such backup files
This commit adds a check before saving categories list info to the
backup file. The check is the same check which is used while backing up
category info of manga in library
Tested and worked successfully on app installed on Android 12
(cherry picked from commit 11c01235ac)
(cherry picked from commit 1269d71d1a)
nicki
4cee1b3583