[twitter] add 'username-alt' option (#5715)

docs/configuration.rst

@@ -4105,6 +4105,18 @@ Description
     Ignore previously seen Tweets.
 
 
+extractor.twitter.username-alt
+------------------------------
+Type
+    ``string``
+Description
+    Alternate Identifier (username, email, phone number)
+    when `logging in <extractor.*.username & .password_>`__.
+
+    When not specified and asked for by Twitter,
+    this identifier will need to entered in an interactive prompt.
+
+
 extractor.twitter.users
 -----------------------
 Type

gallery_dl/extractor/twitter.py

@@ -1854,7 +1854,7 @@ def _login_impl(extr, username, password):
                 },
             }
         elif subtask == "LoginEnterAlternateIdentifierSubtask":
-            alt = extr.input(
+            alt = extr.config("username_alt") or extr.input(
                 "Alternate Identifier (username, email, phone number): ")
             data = {
                 "enter_text": {