check for sub if empty

[brucewzj99]

Describe the bug
When subcategory/subpayment is empty, bot will hang

To Reproduce
Steps to reproduce the behavior:

1. Create a category with no subcategory
2. Try to add the category with no subcategory
3. Bot will hang

Expected behavior
Bot should check that there is no sub category and not show or just choose that category as base

Additional context
Add any other context about the problem here.