Warning: NaN is an invalid value for the height css style property.

[kittaakos]

Describe the problem

I was working on #1161 when I noticed this error in the logs. Note, that the serial monitor was non-functional, so errors were expected, but the IDE2 frontend should handle errors gracefully.

root DEBUG Opening channel for service path '/services/monitor-manager-proxy'. [ID: 34]
root ERROR Warning: `NaN` is an invalid value for the `height` css style property.
    in div (created by List)
    in List (created by SerialMonitorOutput)
    in SerialMonitorOutput
    in div
    in div

To reproduce

I do not have the exact steps, but these steps should help devs to reproduce the defect:

• check out 7d96153,
• start the IDE2,
• Start/stop the monitor.

Expected behavior

IDE2 frontend code can handle when the serial monitor service fails.

Arduino IDE version

7d96153

Operating system

macOS

Operating system version

12.3.1

Additional context

No response

Issue checklist

• I searched for previous reports in the issue tracker
• I verified the problem still occurs when using the latest nightly build
• My report contains all necessary details