Describe the bug

• WebSocketResponse (web_ws.py) inherits from StreamResponse (web_response.py).
• WebSocketResponse overrides prepare with a pre_start and post_start, which sets self._writer to a WebSocketWriter.
• WebSocketResponse does not override the prepared property from StreamResponse
• prepared property checks if self._payload_writer is not None

To Reproduce

wsock = web.WebSocketResponse()
try:
    # Bug can happen when this job times out during `WebSocketResponse `calling `super().prepare()`
    # and `StreamResponse` is inside `await self._start` and client connection is dropped but OS didn't notice
    async with async_timeout(10):
        await wsock.prepare()
except asyncio.TimeoutError:
    if wsock.prepared:
        # This raises because `close()` checks if `self._writer` is not None,
        # which is set inside `StreamResponse._post_start`
        await wsock.close()

Expected behavior

If wsock.prepared returns True, it should be safe to close the connection.

Logs/tracebacks

File "server/api.py", line 264, in handle
    await wsock.close()
  File "aiohttp/web_ws.py", line 329, in close
    raise RuntimeError("Call .prepare() first")

### Python Version

```console
$ python --version
3.9

aiohttp Version

$ python -m pip show aiohttp
3.7.4.post0

multidict Version

$ python -m pip show multidict
5.1.0

yarl Version

$ python -m pip show yarl
1.6.3

OS

Debian

Related component

Server

Additional context

No response

Code of Conduct

• I agree to follow the aio-libs Code of Conduct