Remove Python 3.9+ exclusive code from WebHost options.py.

`str.removeprefix` was added in Python 3.9, so this causes WebHost to return a 500 error if running on Python 3.8.

Generate.py

@@ -446,14 +446,6 @@ def handle_option(ret: argparse.Namespace, game_weights: dict, option_key: str,
 
 
 def roll_settings(weights: dict, plando_options: PlandoOptions = PlandoOptions.bosses):
-    """
-    Roll options from specified weights, usually originating from a .yaml options file.
-
-    Important note:
-    The same weights dict is shared between all slots using the same yaml (e.g. generic weights file for filler slots).
-    This means it should never be modified without making a deepcopy first.
-    """
-
     from worlds import AutoWorldRegister
 
     if "linked_options" in weights:

WebHostLib/options.py

@@ -234,7 +234,7 @@ def generate_yaml(game: str):
         # Detect random-* keys and set their options accordingly
         for key, val in options.copy().items():
             if key.startswith("random-"):
-                options[key.removeprefix("random-")] = "random"
+                options[key[len("random-"):]] = "random"
                 del options[key]
 
         # Error checking

worlds/musedash/MuseDashData.txt

@@ -553,7 +553,7 @@ NOVA|73-4|Happy Otaku Pack Vol.19|True|6|8|10|
 Heaven's Gradius|73-5|Happy Otaku Pack Vol.19|True|6|8|10|
 Ray Tuning|74-0|CHUNITHM COURSE MUSE|True|6|8|10|
 World Vanquisher|74-1|CHUNITHM COURSE MUSE|True|6|8|10|11
-Territory Battles|74-2|CHUNITHM COURSE MUSE|True|5|7|9|
+Tsukuyomi Ni Naru|74-2|CHUNITHM COURSE MUSE|False|5|7|9|
 The wheel to the right|74-3|CHUNITHM COURSE MUSE|True|5|7|9|11
 Climax|74-4|CHUNITHM COURSE MUSE|True|4|8|11|11
 Spider's Thread|74-5|CHUNITHM COURSE MUSE|True|5|8|10|12