fix(ICC/Deathbringer Saurfang) NPC Muradin Dialogues

[pangolp]

Changes Proposed:

This PR proposes changes to:

• [x] Core (units, players, creatures, game systems).
• [x] Scripts (bosses, spell scripts, creature scripts).

Issues Addressed:

• Closes https://github.com/azerothcore/azerothcore-wotlk/issues/8921
• Closes https://github.com/azerothcore/azerothcore-wotlk/pull/13506

Tests Performed:

This PR has been:

• [x] Tested in-game by the author.

How to Test the Changes:

1. .tele IcecrownCitadel
2. Eliminate the first 3 bosses, and then start the fourth fight. Without the pull request, the script is not updated, and the dialogs are displayed incorrectly. I don't know if there is another way to do it, but I looked for thousands of ways, and the only one that occurred to me, as a final point, to fix it, until a better way appears, was this.

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For example: if a PR fixes spell X by changing a part of code that handles spells X, Y, and Z, we should not only test X, but we should test Y and Z as well.