[bug] Crash if MIDI device is unavailable (Linux)

[OPNA2608]

Describe the bug
Attempting to launch st without ALSA's sequencer kernel module snd_seq loaded crashes the application in an uncaught exception, due to /dev/snd/seq being unavailable.

To Reproduce

1. Launch a system without the snd_seq kernel module.
2. Launch st.
3. Crash.

Expected behavior

1. Exception should be caught and handled gracefully, just like for the regular sound device being unavailable.
2. snd_seq shouldn't be a hard requirement, if I never plan to attach a MIDI device into my system.

Screenshots

Desktop (please complete the following information):

• OS: postmarketOS 1.23.0 aarch64
• Version 0.2.0

Additional context
Unusual system, but the core issue still exists.