Velocity reload bug

[Pantera07]

If query is disabled(enabled = false), velocity reload bug occurs when I change the query port.

How to reproduce:

1. Change velocity.toml (query port)
2. Run 'velocity reload' command

Related?: #915

> velocity reload
[15:57:35 ERROR]: Unable to reload configuration
java.lang.NullPointerException: Cannot invoke "com.velocitypowered.proxy.network.Endpoint.getType()" because "endpoint" is null
        at com.velocitypowered.proxy.network.ConnectionManager.close(ConnectionManager.java:182) ~[velocity-3.3.0-SNAPSHOT-390.jar:3.3.0-SNAPSHOT (git-afd8b55f-b390)]
        at com.velocitypowered.proxy.VelocityServer.reloadConfiguration(VelocityServer.java:473) ~[velocity-3.3.0-SNAPSHOT-390.jar:3.3.0-SNAPSHOT (git-afd8b55f-b390)]
        at com.velocitypowered.proxy.command.builtin.VelocityCommand$Reload.run(VelocityCommand.java:133) ~[velocity-3.3.0-SNAPSHOT-390.jar:3.3.0-SNAPSHOT (git-afd8b55f-b390)]
        at com.mojang.brigadier.CommandDispatcher.execute(CommandDispatcher.java:262) ~[velocity-3.3.0-SNAPSHOT-390.jar:3.3.0-SNAPSHOT (git-afd8b55f-b390)]
        at com.velocitypowered.proxy.command.VelocityCommandManager.executeImmediately0(VelocityCommandManager.java:230) ~[velocity-3.3.0-SNAPSHOT-390.jar:3.3.0-SNAPSHOT (git-afd8b55f-b390)]
        at com.velocitypowered.proxy.command.VelocityCommandManager.lambda$executeAsync$0(VelocityCommandManager.java:268) ~[velocity-3.3.0-SNAPSHOT-390.jar:3.3.0-SNAPSHOT (git-afd8b55f-b390)]
        at java.base/java.util.concurrent.CompletableFuture$UniApply.tryFire(CompletableFuture.java:646) ~[?:?]
        at java.base/java.util.concurrent.CompletableFuture$Completion.run(CompletableFuture.java:482) ~[?:?]
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144) ~[?:?]
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642) ~[?:?]
        at java.base/java.lang.Thread.run(Thread.java:1583) [?:?]
[15:57:35 INFO]: Unable to reload your Velocity configuration. Check the console for more details.