Replication fix amendment to #778

[mdprotacio]

No description provided.

[kloining]

I implemented this PR manually in my repository, and it solved a number of issues:

• Fixed the stats for a channel, the number could also be a negative number, resulting in a permanent breakdown
• This resulted in a replica to unsubscribe from redis, stopping broadcasts to the channel on other servers.
  Please get this checked and merged :)

[mpociot]

Thank you for the PR @mdprotacio

[erikn69]

There was 1 failure:

1) BeyondCode\LaravelWebSockets\Test\FetchChannelTest::test_it_returns_404_for_invalid_channels
Failed asserting that two arrays are identical.
--- Expected
+++ Actual
@@ @@
 Array &0 (
-    'occupied' => true
-    'subscription_count' => 2
+    'occupied' => false
+    'subscription_count' => 0
 )

/home/runner/work/laravel-websockets/laravel-websockets/tests/FetchChannelTest.php:129
phpvfscomposer:///home/runner/work/laravel-websockets/laravel-websockets/vendor/phpunit/phpunit/phpunit:60

[genesiscz]

This seems to introduce a new problem:

PHP Warning: Undefined property: Ratchet\Server\IoConnection::$lastPongedAt in /data/.../vendor/cboden/ratchet/src/Ratchet/AbstractConnectionDecorator.php on line 31