Crash when analog input config doesn't have an onChange element

[neilenns]

Describe the bug
Mobiflight crashes if you somehow get your config file into a situation where the Analog input config doesn't have an onChange element.

Steps To Reproduce
Steps to reproduce the behavior:

Open this file in MobiFlight: PMDG 738v1 AAL.old.zip

Expected behavior
No crash

Actual behavior
Crash

Problem is here:

MobiFlight-Connector/UI/Panels/OutputConfigPanel.cs

Line 661 in d36f737

row["OutputName"] = cfgItem.AnalogInputConfig.onChange.GetType().ToString().Replace("MobiFlight.InputConfig.", "");