[Onyxia] Onyxia cleave timer

### What client do you play on?

ruRU

### Faction

- [ ] Alliance
- [X] Horde

### Content Phase:

- [ ] Generic
- [ ] 1-19
- [ ] 20-29
- [ ] 30-39
- [ ] 40-49
- [ ] 50-59
- [X] 60

### Current Behaviour

Looks like the wrong timer for Ony's cleave. Now you can very often see two cleaves in a row. And in general it's very often used.

### Expected Blizzlike Behaviour

Usually used no more than every 3-4 attacks and never in a row

### Source

I don't have reliable sources. Only a number of videos and logs indirectly pointing to this :
https://www.youtube.com/watch?v=qF15Gn4NBeU
https://www.youtube.com/watch?v=_z1aFJ4gq40
https://www.youtube.com/watch?v=OXhkYlwYIz4
https://www.youtube.com/watch?v=EZPoPfot5iM
https://www.youtube.com/watch?v=chH0oLeXR2o
https://vanilla.warcraftlogs.com/reports/KAG9WxHNYagRPmfT#fight=3&type=casts&hostility=1&source=45
https://vanilla.warcraftlogs.com/reports/PmN7vJcQhCqMDag1#fight=2&type=casts&hostility=1&source=49
https://vanilla.warcraftlogs.com/reports/TPtw2X8kJdAVb6nv#fight=3&type=casts&hostility=1&source=52
https://vanilla.warcraftlogs.com/reports/Hb1VTzLFa8D2j9nt#fight=3&type=casts&hostility=1&source=53
https://vanilla.warcraftlogs.com/reports/rgFv219RhcCHxV7w#fight=4&type=casts&hostility=1&source=29
https://vanilla.warcraftlogs.com/reports/BQ6pTmX1rk7bKwtY#fight=3&type=casts&hostility=1&source=35

### Steps to reproduce the problem

123

### Extra Notes
https://github.com/chromiecraft/chromiecraft/issues/2920

### AC rev. hash/commit

https://github.com/chromiecraft/azerothcore-wotlk/commit/6f20b9ece71984f1a11469e65ede8accda05653e

### Operating system

Ubuntu 20.04

### Modules

- [mod-ah-bot](https://github.com/azerothcore/mod-ah-bot)
- [mod-cfbg](https://github.com/azerothcore/mod-cfbg)
- [mod-chat-transmitter](https://github.com/azerothcore/mod-chat-transmitter)
- [mod-chromie-xp](https://github.com/azerothcore/mod-chromie-xp)
- [mod-desertion-warnings](https://github.com/azerothcore/mod-desertion-warnings)
- [mod-duel-reset](https://github.com/azerothcore/mod-duel-reset)
- [mod-eluna-lua-engine](https://github.com/azerothcore/mod-eluna-lua-engine)
- [mod-ip-tracker](https://github.com/azerothcore/mod-ip-tracker)
- [mod-low-level-arena](https://github.com/azerothcore/mod-low-level-arena)
- [mod-multi-client-check](https://github.com/azerothcore/mod-multi-client-check)
- [mod-pvp-titles](https://github.com/azerothcore/mod-pvp-titles)
- [mod-pvpstats-announcer](https://github.com/azerothcore/mod-pvpstats-announcer)
- [mod-queue-list-cache](https://github.com/azerothcore/mod-queue-list-cache)
- [mod-server-auto-shutdown](https://github.com/azerothcore/mod-server-auto-shutdown)
- [mod-save-inventory](https://github.com/Nyeriah/mod-save-inventory)
- [lua-carbon-copy](https://github.com/55Honey/Acore_CarbonCopy)
- [lua-exchange-npc](https://github.com/55Honey/Acore_ExchangeNpc)
- [lua-custom-worldboss](https://github.com/55Honey/Acore_CustomWorldboss)
- [lua-level-up-reward](https://github.com/55Honey/Acore_LevelUpReward)
- [lua-recruit-a-friend](https://github.com/55Honey/Acore_RecruitAFriend)
- [lua-send-and-bind](https://github.com/55Honey/Acore_SendAndBind)
- [lua-temp-announcements](https://github.com/55Honey/Acore_TempAnnouncements)
- [lua-zonecheck](https://github.com/55Honey/acore_Zonecheck)
- [lua-zone-debuff](https://github.com/55Honey/Acore_ZoneDebuff)

### Customizations

None

### Server

ChromieCraft

Start by reproducing Onyxia's cleave behavior on the ruRU Horde level-60 setup and compare the cast spacing with the linked videos and Warcraft Logs reports. Review the progression-system behavior at AC commit 6f20b9ece71984f1a11469e65ede8accda05653eaccda05653e and the related ChromieCraft issue #2920; done means cleaves no longer occur consecutively and match the expected attack spacing.

Written by the indexing model from the issue text.