No completion message is printed when a library is installed

[alranel]

When installing a library, the output panel shows the progress messages but does not inform user about the completion of the task.

For instance, when installing the ArduinoIoTCloud library, the output panel contains:

downloading MKRNB@1.5.1: false%
downloading : false%
downloading : true%
downloading ArduinoECCX08@1.3.5: false%
downloading : false%
downloading : true%
downloading RTCZero@1.6.0: false%
downloading : false%
downloading : true%
downloading WiFiNINA@1.8.5: false%
downloading : false%
downloading : true%
downloading MKRGSM@1.5.0: false%
downloading : false%
downloading : true%
downloading ArduinoIoTCloud@0.13.1: false%
downloading : false%
downloading : false%
downloading : true%
downloading WiFi101@0.16.1: false%
downloading : false%
downloading : true%
downloading Arduino_ConnectionHandler@0.6.3: false%
downloading : false%
downloading : true%
downloading Arduino_DebugUtils@1.1.0: false%
downloading : false%
downloading : true%
downloading ArduinoMqttClient@0.1.5: false%
downloading : false%
downloading : true%
downloading MKRWAN@1.0.15: false%
downloading : false%
downloading : true%

As a user, I don't know if the process is completed or not.

Also, those downloading : false% are not much meaningful.

[per1234]

Closing as fixed by #305