fix(Scripts/Hyjal): Fix hyjal trash

[Exitare]

I replaced the static fix with a dynamic one, that only triggers for the first wave for the first boss. Which is in my understanding Winterchill. All subsequent encounters will always apply rep gain.

Changes Proposed:

This PR proposes changes to:

• Core (units, players, creatures, game systems).
• Scripts (bosses, spell scripts, creature scripts).
• Database (SAI, creatures, etc).

Issues Addressed:

• Closes Mount Hyjal, Wave 9 of Hyjal invaders doesnt give you reputation chromiecraft/chromiecraft#7684

SOURCE:

The changes have been validated through:

• Live research (checked on live servers, e.g Classic WotLK, Retail, etc.)
• Sniffs (remember to share them with the open source community!)
• Video evidence, knowledge databases or other public sources (e.g forums, Wowhead, etc.)
• The changes promoted by this pull request come partially or entirely from another project (cherry-pick). Cherry-picks must be committed using the proper --author tag in order to be accepted, thus crediting the original authors, unless otherwise unable to be found

Tests Performed:

This PR has been:

• Tested in-game by the author.
• Tested in-game by other community members/someone else other than the author/has been live on production servers.
• This pull request requires further testing and may have edge cases to be tested.

How to Test the Changes:

• This pull request can be tested by following the reproduction steps provided in the linked issue
• This pull request requires further testing. Provide steps to test your changes. If it requires any specific setup e.g multiple players please specify it as well.

Two ways to tests: (Both must pass)

1. Start a new raid, kill the first wave (No rep gain). Play until the first boss spawns, kill it. Start next wave counter. The first wave should now provide rep.

2. Start a new raid, kill the first wave (No rep gain). Kill the first boss. Do no start the next wave counter. Leave the raid or restart the server. The event needs to be interrupted. Restart the server, start the new wave timer. First new wave should provide rep.

Known Issues and TODO List:

• [ ]
• [ ]

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