Core/Spells: Fix 79528 Potion of Shrouding

Fixes Potion of Shrouding (79528) requiring the player to manually target themselves before using the item.

The spell has implicit target NONE in DB2, causing item use without a selected target to fail with invalid target.

This updates the spell fixup to:
- Use the caster as implicit target
- Set explicit target masks to allied unit so item use can resolve the caster as fallback target

Tested:
- Using Potion of Shrouding from item without targeting self works
- Cooldown behavior remains handled by normal item spell path

src/server/game/Spells/SpellMgr.cpp

@@ -3632,6 +3632,19 @@ void SpellMgr::LoadSpellInfoCorrections()
         });
     });
 
+	// Potion of Shrouding
+	ApplySpellFix({ 79528 }, [](SpellInfo* spellInfo)
+	{
+		spellInfo->ExplicitTargetMask = TARGET_FLAG_UNIT_ALLY;
+		spellInfo->RequiredExplicitTargetMask = TARGET_FLAG_UNIT_ALLY;
+
+		ApplySpellEffectFix(spellInfo, EFFECT_0, [](SpellEffectInfo* spellEffectInfo)
+		{
+			spellEffectInfo->TargetA = SpellImplicitTargetInfo(TARGET_UNIT_CASTER);
+			spellEffectInfo->TargetB = SpellImplicitTargetInfo();
+		});
+	});
+
     ApplySpellFix({
         56690, // Thrust Spear
         60586, // Mighty Spear Thrust