Added unobtainable items to config (#2133)

# Pull Request

Moving hardcoded values to config

## How to Test the Changes

- use maintenance command
- unequip and destroy item get from this command
- turn off server
- add item to config
- turn on server
- use maintenace command
- check that different item was provided

## Complexity & Impact

Does this change add new decision branches?
- - [X] No
- - [ ] Yes (**explain below**)

Does this change increase per-bot or per-tick processing?
- - [X] No
- - [ ] Yes (**describe and justify impact**)

Could this logic scale poorly under load?
- - [X] No
- - [ ] Yes (**explain why**)
---

## Defaults & Configuration

Does this change modify default bot behavior?
- - [X] No
- - [ ] Yes (**explain why**)
---

## AI Assistance

Was AI assistance (e.g. ChatGPT or similar tools) used while working on
this change?
- - [X] No
- - [ ] Yes (**explain below**)

---

## Final Checklist

- - [X] Stability is not compromised
- - [X] Performance impact is understood, tested, and acceptable
- - [X] Added logic complexity is justified and explained
- - [X] Documentation updated if needed

---

## Notes for Reviewers

conf/playerbots.conf.dist

@@ -796,6 +796,10 @@ AiPlayerbot.LimitGearExpansion = 1
 # Set between 0 (0%) and 1 (100%)
 AiPlayerbot.RandomGearLoweringChance = 0
 
+# Unobtainable or unusable items (comma-separated list of item IDs)
+# Default: Chilton Wand (12468), Totem of the Earthen Ring (46978)
+AiPlayerbot.UnobtainableItems = 12468,46978
+
 # Randombots check player's gearscore level and deny the group invitation if it's too low
 # Default: 0 (disabled)
 AiPlayerbot.GearScoreCheck = 0
@@ -2213,4 +2217,4 @@ AiPlayerbot.SummonAtInnkeepersEnabled = 1
 # 30% more damage, 40% damage reduction (tank bots), increased all resistances, reduced threat for non tank bots, increased threat for tank bots.
 # Buffs will be applied on PP, Sindragosa and Lich King
 
-AiPlayerbot.EnableICCBuffs = 1
+AiPlayerbot.EnableICCBuffs = 1