[yt-dlp] Make _Params["paths"] a Mapping[str, str]

`paths` accepts a dict of output paths (keys: 'home', 'temp', and OUTTMPL_TYPES keys).
Typing it as `Mapping[str, str] | None` matches runtime behavior and avoids false positives
when passing a dict to YoutubeDL params.

Author: Marcin795

stubs/yt-dlp/yt_dlp/__init__.pyi

@@ -105,7 +105,7 @@ class _Params(TypedDict, total=False):
     listformats: bool | None
     outtmpl: str | Mapping[str, str] | None
     outtmpl_na_placeholder: str | None
-    paths: str | None
+    paths: Mapping[str, str] | None
     restrictfilenames: bool | None
     windowsfilenames: bool | None
     ignoreerrors: bool | Literal["only_download"] | None