Use `telnetlib3` instead of the obsolete `telnetlib`. #1920

Job	Run time
MSIS code validation (ubuntu-latest)	7s
XML validation	11s
MSIS code validation (macos-latest)	13s
C/C++ build (MSVC) (ON)	5m 44s
C/C++ build (MinGW) (ON)	4m 50s
C/C++ build (MSVC) (OFF)	2m 41s
C/C++ build (MinGW) (OFF)	3m 50s
C/C++ build (MacOSX) (macos-13, 3.8)	4m 9s
C/C++ build (Linux) (ubuntu-22.04, ON, ON, OFF, ON)	3m 54s
C/C++ build (Linux) (ubuntu-22.04, ON, OFF, OFF, ON)	3m 50s
C/C++ build (Linux) (ubuntu-22.04, OFF, ON, OFF, ON)	3m 41s
C/C++ build (MacOSX) (macos-14, 3.10)	2m 19s
C/C++ build (Linux) (ubuntu-22.04, OFF, OFF, OFF, ON)	3m 51s
C/C++ build (Linux) (ubuntu-20.04, OFF, OFF, ON, OFF)	5m 20s
Build Python Module from Source	0s
Code coverage	1m 56s
Matlab S-Function	0s
Build Python wheels	0s
Build Windows installer	0s
Deploy Rolling Release	0s
Deploy Stable Release	0s
Deploy Documentation	0s
	46m 36s

Provide feedback