[BUG]-Searching a large VTC directory causes MC to drop

[andrew-welker]

Describe the bug
When searching large directories directly from a codec, responses take a long time to return. This causes the Mobile Control interface to drop. In addition, a null reference exception occurs during the search process.

Stacktrace

Include a stack trace of the exception if possible.

[14:17:22.862]App 1:[appServer] Message RX: {"type":"/device/videoCodec/directorySearch","content":{"value":"must"},"clientId":11}
[14:17:23.405]App 1:[ciscoSparkPlusCodec-1] Error Deserializing feedback from codec: System.NullReferenceException: NullReferenceException
   at PepperDash.Essentials.Devices.Common.VideoCodec.Cisco.CiscoSparkCodec.DeserializeResponse(String response)
   at PepperDash.Essentials.Devices.Common.VideoCodec.Cisco.CiscoSparkCodec.Port_LineReceived(Object dev, GenericCommMethodReceiveTextArgs args)
   at PepperDash.Core.CommunicationGather.Port_TextReceivedStringDelimiter(Object sender, GenericCommMethodReceiveTextArgs args)
   at PepperDash.Core.GenericSshClient.Stream_DataReceived(Object sender, ShellDataEventArgs e)
   at Crestron.SimplSharp.Ssh.ShellStream.g(Byte[] A_0)
   at Crestron.SimplSharp.Ssh.ShellStream.e(Object A_0, ChannelDataEventArgs A_1)
   at Crestron.SimplSharp.Ssh.Channels.Channel.OnData(Byte[] data)
   at Crestron.SimplSharp.Ssh.Channels.Channel.o(Object A_0, MessageEventArgs`1 A_1)
   at Crestron.SimplSharp.Ssh.Session.OnChannelDataReceived(ChannelDataMessage message)
   at Crestron.SimplSharp.Ssh.Session.aq(ChannelDataMessage A_0)
   at System.Reflection.RuntimeMethodInfo.InternalInvoke(RuntimeMethodInfo rtmi, Object obj, BindingFlags invokeAttr, Binder binder, Object parameters, CultureInfo culture, Boolean isBinderDefault, Assembly caller, Boolean verifyAccess, StackCrawlMark& stackMark)
   at System.Reflection.RuntimeMethodInfo.InternalInvoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean verifyAccess, StackCrawlMark& stackMark)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at System.Reflection.MethodBase.Invoke(Object obj, Object[] parameters)
   at Crestron.SimplSharp.Ssh.Session.a1(Message A_0)
   at Crestron.SimplSharp.Ssh.Session.h()
   at Crestron.SimplSharp.Ssh.Session.c()
   at Crestron.SimplSharp.Ssh.Session.<>c__DisplayClass37.<ExecuteThread>b__36(Object o)
   at System.Threading.ThreadPool.WorkItem.doWork(Object o)
   at System.Threading.Timer.ring()