Feature: Requires an instance-specific switch

### Describe your feature request or suggestion in detail

I'm using both the https://github.com/azerothcore/mod-autobalance and https://github.com/azerothcore/mod-zone-difficulty plugins. I use mod-zone-difficulty to implement the Mythic Raid function. Can I quickly set the difficulty coefficient of a specific instance of dungeon to 1 (the dungeon has autobalance turned on)

### Describe a possible solution to your feature or suggestion in detail

There is a header file ZoneDifficulty.h that I tried to reference and use in autobalance.

sZoneDifficulty->MythicmodeInstanceData.find(instanceId) == sZoneDifficulty->MythicmodeInstanceData.end()

Able to determine whether the instance has the zone-difficulty module enabled

### Additional context

_No response_

Start by reading ZoneDifficulty.h and the interaction between mod-autobalance and mod-zone-difficulty. Trace how MythicmodeInstanceData is checked for an instanceId, then determine the intended instance-specific coefficient behavior and validate it in a dungeon with autobalance enabled.

Written by the indexing model from the issue text.