For run_command, not all output ends in \n\r

[makermelissa]

For instance, when packages are downloaded, the output line should only have a \r in order to update the percentage done. However, https://github.com/adafruit/Adafruit_Python_Shell/blob/main/adafruit_shell.py#L95 and https://github.com/adafruit/Adafruit_Python_Shell/blob/main/adafruit_shell.py#L92 always print a \n\r resulting in larger packages that were supposed to update a percent actually appear on separate lines. It's not super important, but would make this library better match the actual command output better.