Remove attribute no longer needed

The limit of the anycast channel's buffer is no longer needed
as the same information is already stored in the deque's maxlen
property.

src/frequenz/channels/_anycast.py

@@ -67,9 +67,6 @@ def __init__(self, maxsize: int = 10) -> None:
         Args:
             maxsize: Size of the channel's buffer.
         """
-        self.limit: int = maxsize
-        """The maximum number of values that can be stored in the channel's buffer."""
-
         self.deque: Deque[T] = deque(maxlen=maxsize)
         """The channel's buffer."""