feat(nickname): 删除昵称系统相关功能 (#2114)

删除了昵称系统的完整实现，包括：
- 移除 nickname.py 插件文件及其所有功能代码
- 从 FriendUser 和 GroupInfoUser 模型中删除 nickname 字段
- 移除相关的数据库配置
- 更新 GroupManager 中的操作者名称获取逻辑
- 简化平台处理的数据源代码

zhenxun/builtin_plugins/platform/qq/group_handle/data_source.py

@@ -40,9 +40,7 @@ _REFRESH_TASKS: set[asyncio.Task] = set()
 
 
 def _normalize_platform(platform: str | set[str] | None) -> str | None:
-    if isinstance(platform, set):
-        return next(iter(platform), None)
-    return platform
+    return next(iter(platform), None) if isinstance(platform, set) else platform
 
 
 async def _safe_get_group_member_info(bot: Bot, group_id: str, user_id: str) -> dict:
@@ -409,12 +407,11 @@ class GroupManager:
                 operator_user = await GroupInfoUser.get_or_none(
                     user_id=operator_id, group_id=group_id
                 )
-                if operator_user:
-                    operator_name = (
-                        operator_user.nickname or operator_user.user_name or operator_id
-                    )
-                else:
-                    operator_name = operator_id
+                operator_name = (
+                    (operator_user.user_name or operator_id)
+                    if operator_user
+                    else operator_id
+                )
             else:
                 operator_name = ""
             return f"{user_name} 被 {operator_name} 送走了."