[facebook:set] fix/improve 'user_id' extraction (#7848)

https://github.com/mikf/gallery-dl/issues/7848#issuecomment-3181428631

gallery_dl/extractor/facebook.py

@@ -80,6 +80,8 @@ class FacebookExtractor(Extractor):
             directory["user_id"] = (
                 text.extr(
                     set_page, '"actors":[{"__typename":"User","id":"', '"') or
+                text.extr(
+                    set_page, '"userID":"', '"') or
                 directory["set_id"].split(".")[1])
 
         return directory

test/results/facebook.py

@@ -143,6 +143,22 @@ __tests__ = (
     "#count"   : 4,
 },
 
+{
+    "#url"     : "https://www.facebook.com/media/set/?set=a.127331797422780&type=3",
+    "#comment" : "pfbid user ID; 'This content isn't available right now' profile",
+    "#class"   : facebook.FacebookSetExtractor,
+    "#metadata": "post",
+    "#range"   : 0,
+
+    "caption"   : "Amarte es mi hábito favorito",
+    "date"      : "dt:2025-05-03 03:42:52",
+    "set_id"    : "a.127331797422780",
+    "title"     : "Profile pictures",
+    "user_id"   : "100004378810826",
+    "user_pfbid": r"re:pfbid\w{64}",
+    "username"  : "Angel Nava Santiago",
+},
+
 {
     "#url"     : "https://www.facebook.com/photo.php?fbid=10165113568399554&set=t.100064860875397&type=3",
     "#class"   : facebook.FacebookPhotoExtractor,