Align default prevent proxy connection settings with the default config file

This option generally creates a bunch of oddities in many setups, defaulting to false
as per the default toml config, is probably the better option here

proxy/src/main/java/com/velocitypowered/proxy/config/VelocityConfiguration.java

@@ -503,7 +503,7 @@ public class VelocityConfiguration implements ProxyConfig {
       final boolean forceKeyAuthentication = config.getOrElse("force-key-authentication", true);
       final boolean announceForge = config.getOrElse("announce-forge", true);
       final boolean preventClientProxyConnections = config.getOrElse(
-              "prevent-client-proxy-connections", true);
+              "prevent-client-proxy-connections", false);
       final boolean kickExisting = config.getOrElse("kick-existing-players", false);
       final boolean enablePlayerAddressLogging = config.getOrElse(
               "enable-player-address-logging", true);