Fix P100 errors on multi-requests (#930)

Fixes an issue reported by @bdraco with the P100 not working in the
latest branch:

`[Errno None] Can not write request body for HOST_REDACTED,
ClientOSError(None, 'Can not write request body for
URL_REDACTED'))`

Issue caused by the number of multi requests going above the default
batch of 5 and the P100 not being able to handle the second multi
request happening immediately as it closes the connection after each
query (See https://github.com/python-kasa/python-kasa/pull/690 for
similar issue). This introduces a small wait time on concurrent requests
once the device has raised a ClientOSError.

kasa/aestransport.py

@@ -6,7 +6,6 @@ under compatible GNU GPL3 license.
 
 from __future__ import annotations
 
-import asyncio
 import base64
 import hashlib
 import logging
@@ -74,7 +73,6 @@ class AesTransport(BaseTransport):
     }
     CONTENT_LENGTH = "Content-Length"
     KEY_PAIR_CONTENT_LENGTH = 314
-    BACKOFF_SECONDS_AFTER_LOGIN_ERROR = 1
 
     def __init__(
         self,
@@ -216,7 +214,6 @@ class AesTransport(BaseTransport):
                     self._default_credentials = get_default_credentials(
                         DEFAULT_CREDENTIALS["TAPO"]
                     )
-                    await asyncio.sleep(self.BACKOFF_SECONDS_AFTER_LOGIN_ERROR)
                 await self.perform_handshake()
                 await self.try_login(self._get_login_params(self._default_credentials))
                 _LOGGER.debug(