Fix fomod_controller not having commands cleared

Commit a7c06aa broke the fomod
controller by making it fail to clear commands from the last page. If
one of these commands were executed, it would result in a crash.

ammo/fomod_controller.py

@@ -141,8 +141,8 @@ def populate_index_commands(self) -> None:
         # Remove all attributes that are numbers
         for i in list(self.__dict__.keys()):
             try:
-                int(i)
-                del self.__dict__[f"do_{i}"]
+                int(i.lstrip("do_"))
+                del self.__dict__[i]
             except ValueError:
                 pass
         for i in range(len(self.page.selections)):