feat: disable prograss bar if terminal is serial port

[eatradish]

No description provided.

[MingcongBai]

Detecting serial consoles (or slow consoles, as we initially set to find out) via ioctl() or file descriptors is probably a bust, for the record (and those who come after us):

• Serial consoles can still get/set window sizes via (or for that matter, has) TIOCGWINSZ and TIOCSWINSZ.
• While real TTY/serial console shell sessions may identify themselves as /dev/tty[A-Z]* and not /dev/tty[1..9999999] or /dev/pts/* as found with SSH/Tmux/... via /proc/self/fd/0, the program itself will still find themselves in pseudo terminals.

We'd need a more robust way to do this - or maybe there are other ideas?

[MingcongBai]

Unfortunately, the interface still flickers, but not as much - it could be due to the fact that multiple elements were updated at the same time.

The latency on serial terminals are still low, however, so that might not have helped too much.