[reddit] use '"videos": "dash"' by default (#8657)

https://github.com/mikf/gallery-dl/issues/8657#issuecomment-3663560902

docs/configuration.rst

@@ -5218,7 +5218,7 @@ Type
     * ``bool``
     * ``string``
 Default
-    ``true``
+    ``"dash"``
 Description
     Control video download behavior.
 

docs/gallery-dl.conf

@@ -694,7 +694,7 @@
             "previews"    : true,
             "recursion"   : 0,
             "selftext"    : null,
-            "videos"      : true
+            "videos"      : "dash"
         },
         "redgifs":
         {

gallery_dl/extractor/reddit.py

@@ -33,11 +33,11 @@ class RedditExtractor(Extractor):
         previews = self.config("previews", True)
         embeds = self.config("embeds", True)
 
-        if videos := self.config("videos", True):
-            if videos == "ytdl":
-                self._extract_video = self._extract_video_ytdl
-            elif videos == "dash":
+        if videos := self.config("videos", "dash"):
+            if videos == "dash":
                 self._extract_video = self._extract_video_dash
+            elif videos == "ytdl":
+                self._extract_video = self._extract_video_ytdl
             videos = True
 
         selftext = self.config("selftext")