refactor(hero): 移除 Boss 阶段描边相关未实现的代码

清理了 Boss 阶段描边功能的相关代码，包括移除了 resetPhaseOutline 和 setPhaseOutline 方法，删除了相关材质定义，将 onPhaseEnter 方法置空待后续迭代实现。

assets/script/game/common/config/heroSet.ts

@@ -1,4 +1,4 @@
-import { v3 } from "cc"
+import { v3 } from "cc"
 import { BoxSet, FacSet, FightSet } from "./GameSet"
 import { SkillOverrides, TGroup, SkillSet, FieldSkillSet, SkillConfig, SkillKind, FieldSkillConfig, FieldSkillType, mergeSkillParams, BuffTarget } from "./SkillSet"
 import { BuffList, BuffConfig, ModOp } from "./BuffSet"