Heatbeat for azure.messaging.webpubsubclient

**Is your feature request related to a problem? Please describe.**

When connected to both the sync and async WebPubSubClient, I get the following messages every ~20 seconds when there is no traffic going over the websocket.

**Sync**
```
2025-07-22 15:06:10,767 - azure.messaging.webpubsubclient._client - WARNING - An error occurred when trying to connect: Connection to remote host was lost.
2025-07-22 15:06:10,767 - azure.messaging.webpubsubclient._client - INFO - WebSocket connection closed. Code: None, Reason: None
2025-07-22 15:06:10,987 - websocket - INFO - Websocket connected
2025-07-22 15:06:10,987 - azure.messaging.webpubsubclient._client - INFO - connected successfully
...
2025-07-22 15:06:31,290 - azure.messaging.webpubsubclient._client - WARNING - An error occurred when trying to connect: Connection to remote host was lost.
2025-07-22 15:06:31,290 - azure.messaging.webpubsubclient._client - INFO - WebSocket connection closed. Code: None, Reason: None
2025-07-22 15:06:31,637 - websocket - INFO - Websocket connected
2025-07-22 15:06:31,637 - azure.messaging.webpubsubclient._client - INFO - connected successfully
```

**Async**
```
2025-07-22 15:08:46,937 - azure.messaging.webpubsubclient.aio._client - INFO - WebSocket connection closed. Code: None, Reason: None
2025-07-22 15:08:47,085 - azure.messaging.webpubsubclient.aio._client - INFO - connected successfully
...
2025-07-22 15:09:07,259 - azure.messaging.webpubsubclient.aio._client - INFO - WebSocket connection closed. Code: None, Reason: None
2025-07-22 15:09:08,228 - azure.messaging.webpubsubclient.aio._client - INFO - connected successfully
```

I assume that the socket is closed after ~20 seconds of inactivity and then automatically reopened.

I dove into the codebase, and it looks like the websocket connection being opened under the hood is not making use of the heartbeat functionality built into `aiohttp.connect_ws(..., heartbeat=5)` and `websocket.WebSocketApp.run_forever(ping_interval=5)`

**Describe the solution you'd like**

Adapt both the async and sync WebPubSubClients to properly handle the heartbeat.

I played around with setting `heartbeat=5` on the call to connect_ws, and while I no longer got the disconnects every 20 seconds, I still get the following disconnect message every 5-35 min (there is no fixed frequency of the messages like above).

```
azure.messaging.webpubsubclient.aio._client - WARNING - WebSocket error:
2025-07-22 16:38:29,686 - azure.messaging.webpubsubclient.aio._client - WARNING - WebSocket error: No PONG received after 2.5 seconds
2025-07-22 16:38:29,687 - azure.messaging.webpubsubclient.aio._client - INFO - WebSocket connection closed. Code: 1008, Reason: No PONG received after 2.5 seconds
2025-07-22 16:38:29,687 - azure.messaging.webpubsubclient.aio._client - INFO - Staring a new connection
```

This indicates that the server doesn't always respond with a pong message within 2.5 seconds (`aiohttp.connect_ws` hardcodes the `pong_timeout` as `heartbeat / 2`). Even if we bump the heartbeat to 10 seconds, we still get pong_timeout when the response takes longer than 5 seconds.

On the sync side, I also tried out setting `self._thread = threading.Thread(target=self._ws.run_forever, kwargs={"ping_interval": 5}, daemon=True)`. This seems to be working as expected, as the socket never disconnects (this is because per default, `run_forever` doesn't have a `ping_time`, meaning if the server doesn't respond with a pong, the connection doesn't disconnect unless you also pass `ping_timeout` to `run_forever`.

**Describe alternatives you've considered**

Not sure if there are other alternatives to avoiding this behavior unless we can prevent the server-side from disconnecting the connection after 20 seconds of inactivity.

**Additional context**
python: 3.11.4
```
aiohappyeyeballs==2.6.1
aiohttp==3.12.14
aiosignal==1.4.0
attrs==25.3.0
azure-core==1.35.0
azure-messaging-webpubsubclient==1.1.0
azure-messaging-webpubsubservice==1.3.0
certifi==2025.7.14
charset-normalizer==3.4.2
frozenlist==1.7.0
idna==3.10
isodate==0.7.2
multidict==6.6.3
propcache==0.3.2
pyjwt==2.10.1
requests==2.32.4
six==1.17.0
typing-extensions==4.14.1
urllib3==2.5.0
websocket-client==1.8.0
yarl==1.20.1
```

I vibe-coded 2 evaluation scripts that capture metrics on how often these disconnects happen. But the simplest way to reproduce the messages is to just initialize and open a connection to the client and wait 20 seconds.