fix(webup): Data 声明 desc_v2 字段，避免提交时被 asdict 静默丢弃 (#1666)

Co-authored-by: Noah <17682131+ransxd@users.noreply.github.com>

biliup/plugins/bili_webup.py

@@ -989,6 +989,7 @@ class Data:
     title: str = ''
     desc_format_id: int = 0
     desc: str = ''
+    desc_v2: list = field(default_factory=list)
     dynamic: str = ''
     subtitle: dict = field(init=False)
     tag: Union[list, str] = ''