Update async cluster to handle MaxConnectionsError separately

Add explanatory comment to the exception handling for MaxConnectionsError in the
async cluster implementation, matching the synchronous version.

This ensures consistent behavior between sync and async implementations when
connection pool is exhausted, preventing unnecessary cluster reinitialization.

Author: ngabhanenetskope

redis/asyncio/cluster.py

@@ -814,7 +814,13 @@ async def _execute_command(
                     moved = False
 
                 return await target_node.execute_command(*args, **kwargs)
-            except (BusyLoadingError, MaxConnectionsError):
+            except BusyLoadingError:
+                raise
+            except MaxConnectionsError:
+                # MaxConnectionsError indicates client-side resource exhaustion
+                # (too many connections in the pool), not a node failure.
+                # Don't treat this as a node failure - just re-raise the error
+                # without reinitializing the cluster.
                 raise
             except (ConnectionError, TimeoutError):
                 # Connection retries are being handled in the node's