sik radio config timeout when using mission planner and mono

#### Issue details
Hello, I'm trying to load my telemetry radio config with mission planner but I keep running into timeout errors as seen below. I'm running mission planner on ubuntu with mono. The weird thing is it'll load the version and frequency, but nothing else so I can't try and upload new firmware. I've tried both holybro telemtry radios and random ebay ones, and both error out. I'm able to control the drone with mavproxy and mission planner but can't do anything with the firmware. Let me know if this is user error or if any other logs are needed. Thank you!

Edit: forgot to mention, I am able to do this on windows so I'm guessing it has something to do with mono potentially.


#### Version
Mission planner 1.3.82.build build 1.3.8979.17128 arducopter V3.6.12

#### Platform
[ ] All
[ ] AntennaTracker
[ X ] Copter
[ ] Plane
[ ] Rover
[ ] Sub

#### Airframe type
quadcopter

#### Hardware type
pixhawk

#### Logs
```
INFO MissionPlanner.MAVLinkInterface - set giveComport Base Thread current False new False
INFO MissionPlanner.Comms.WinSerialPort - Closing port /dev/ttyUSB0
INFO MissionPlanner.Radio.Sikradio - Doing Command AT&T
INFO MissionPlanner.Radio.Sikradio -
INFO MissionPlanner.Radio.Sikradio - Doing Command ATI
INFO MissionPlanner.Radio.Sikradio - RFD SiK 2.0 on HM-TRP

INFO MissionPlanner.Radio.Sikradio - Doing Command ATI3
INFO MissionPlanner.Radio.Sikradio - 145

INFO MissionPlanner.Radio.Sikradio - Doing Command ATI2
INFO MissionPlanner.Radio.Sikradio - 78

INFO MissionPlanner.Radio.Sikradio - Doing Command AT&E?
INFO MissionPlanner.Radio.Sikradio - ERROR

INFO MissionPlanner.Radio.Sikradio - Doing Command ATI7
INFO MissionPlanner.Radio.Sikradio - L/R RSSI: 186/177 L/R noise: 47/35 pkts: 8378 txe=0 rxe=215 stx=0 srx=0 ecc=0/0 temp=34 dco=0

INFO MissionPlanner.Radio.Sikradio - Doing Command ATI5
INFO MissionPlanner.Radio.Sikradio - S0:FORMAT=26
S1:SERIAL_SPEED=57
S2:AIR_SPEED=64
S3:NETID=25
S4:TXPOWER=20
S5:ECC=0
S6:MAVLINK=1
S7:OPPRESEND=0
S8:MIN_FREQ=915000
S9:MAX_FREQ=928000
S10:NUM_CHANNELS=50
S11:DUTY_CYCLE=100
S12:LBT_RSSI=0
S13:MANCHESTER=0
S14:RTSCTS=0
S15:MAX_WINDOW=131

CustomMessageBox thread calling Base Thread
```

Start by reproducing the radio configuration timeout on Ubuntu with Mono and follow the MissionPlanner.Radio.Sikradio command sequence shown in the logs. Compare the behavior with Windows, then verify that the complete radio configuration loads and firmware upload can proceed without timing out.

Written by the indexing model from the issue text.