text: Title: Cannot notify/write to a characteristic 
  Body: * bleak version: 0.15.1
  * Python version: 3.8.0
  * Operating System: Windows 11
  * BlueZ version (`bluetoothctl -v`) in case of Linux:
  
  ### Description
  
  I would like to scan for a bluetooth device using `BleakClient`, notify and write to two different characteristics
  
  ### What I Did
  
  ```python
  import asyncio
  from bleak import BleakScanner, BleakClient
  from bleak.backends.winrt.client import BleakClientWinRT
  from bleak.backends.winrt.scanner import BleakScannerWinRT
  
  
  class BLDevice:
      async def scan(self):
          devices = await BleakScanner.discover()
          for d in devices:
              print(d)
  
      def __init__(self, mac_addr: str):
          self.mac_addr = mac_addr
          self.client = None
  
      async def connect(self):
          if not self.client:
              device = await BleakScannerWinRT.find_device_by_address(self.mac_addr, 20)
              self.client = BleakClientWinRT(address_or_ble_device=device)
              if not self.client.is_connected:
                  await self.client.connect()
  
      async def write(self):
          def response_handler(sender, data):
              print("{}: {}".format(sender, data))
  
          await self.connect()
          await self.client.write_gatt_char("0000xxxxx-xxxxx-xxxxx-xxxxx-xxxxxxxxxxxx", str.encode("hello world!"))
  
      async def get_sc(self):
          await self.connect()
          for svc in await self.client.get_services():
              for ch in svc.characteristics:
                  print(ch)
  
  
  if __name__ == '__main__':
      MAC_ADDR = "FF:FF:FF:FF:FF:FF"
      my_device = BLDevice(MAC_ADDR)
      loop = asyncio.get_event_loop()
      loop.run_until_complete(my_device.connect())
      loop.run_until_complete(my_device.write())
  
  ```
  I rant the above code and the following error:
  ```
  Traceback (most recent call last):
    File "C:/workstation/repos/bleak_demo/bleak_demo/run.py", line 32, in write
      await self.client.write_gatt_char("0000xxxxx-xxxxx-xxxxx-xxxxx-xxxxxxxxxxxx", str.encode("hello world!"))
    File "C:\Users\raghu\AppData\Local\pypoetry\Cache\virtualenvs\bleak-demo-xIb3w8Wb-py3.8\lib\site-packages\bleak\backends\winrt\client.py", line 665, in write_gatt_char
      _ensure_success(
    File "C:\Users\raghu\AppData\Local\pypoetry\Cache\virtualenvs\bleak-demo-xIb3w8Wb-py3.8\lib\site-packages\bleak\backends\winrt\client.py", line 107, in _ensure_success
      raise BleakError(f"{fail_msg}: Unreachable")
  bleak.exc.BleakError: Could not write value b'hello world!' to characteristic 000A: Unreachable
  ```
  
  here is the output from Windows bluetooth virtual sniffer
  
  ```
  87	29.147761	TexasIns_ (XXXX-XXX)	localhost ()	SMP	11	Rcvd Security Request: AuthReq: No Bonding
  ```
  