Fix 'System.PlatformNotSupportedException'

[ColdeZhang]

Under some special OS env (such as docker container), may throw exception below:

Unhandled exception. System.PlatformNotSupportedException: The system's ping utility could not be found.
   at System.Net.NetworkInformation.Ping.GetPingProcess(IPAddress address, Byte[] buffer, Int32 timeout, PingOptions options)
   at System.Net.NetworkInformation.Ping.SendWithPingUtilityAsync(IPAddress address, Byte[] buffer, Int32 timeout, PingOptions options)
   at System.Net.NetworkInformation.Ping.SendPingAsyncInternal[TArg](TArg getAddressArg, Func`3 getAddress, Int32 timeout, Byte[] buffer, PingOptions options, CancellationToken cancellationToken)
   at Lagrange.Core.Utility.Network.Icmp.PingAsync(Uri hostIp, Int32 timeout)
   at Lagrange.Core.Internal.Context.SocketContext.OptimumServer(Boolean requestMsf, Boolean useIPv6Network)
   at Lagrange.Core.Internal.Context.SocketContext.Connect()

This PR adding try catch to ensuring that application can continue running without crashing.

[Executor-Cheng]

感谢贡献, 但你需要将代码签名再提交

[ColdeZhang]

感谢贡献, 但你需要将代码签名再提交

好的 已经重新签名并提交