Feature Request: Sync Brave AdBlock Custom Filters

Description of the issue:
Currently, there’s no available option to sync Custom Filters you created on Brave AdBlock.

This is an issue for users who have their custom filter list of elements on websites that are not ads, but they blocked because of X reasons.

Steps to Reproduce (add as many as necessary)
Sync a device to your sync chain. Check Sync Settings, Custom Filters sync option nowhere to be found :thinking:

Reproduces how often:
Every time you want to sync a new device in your sync chain

Brave Version(See the About Brave page in the main menu):

Type of devices currently running on the Sync chain in question:
Basically, any computer device in your sync chain.