Disable ClientAliveInterval by default

It was added to fix context canceled issue, but since the issue
has been fixed differently, let's disable it by default

config.yml.example

@@ -76,7 +76,7 @@ sshd:
   web_listen: "localhost:9122"
   # Maximum number of concurrent sessions allowed on a single SSH connection. Defaults to 10.
   concurrent_sessions_limit: 10
-  # Sets an interval after which server will send keepalive message to a client
+  # Sets an interval after which server will send keepalive message to a client. Disabled by default
   client_alive_interval: 15
   # The server waits for this time (in seconds) for the ongoing connections to complete before shutting down. Defaults to 10.
   grace_period: 10

internal/config/config.go

@@ -86,7 +86,6 @@ var (
 		WebListen:               "localhost:9122",
 		ConcurrentSessionsLimit: 10,
 		GracePeriod:             yamlDuration(10 * time.Second),
-		ClientAliveInterval:     yamlDuration(15 * time.Second),
 		ProxyHeaderTimeout:      yamlDuration(500 * time.Millisecond),
 		ReadinessProbe:          "/start",
 		LivenessProbe:           "/health",