fix(alsa): ALSA template errors during enumeration

[roderickvd]

Reported on Discord:

When enumerating devices I get a lot of alsa errors:

[2025-10-16T22:38:51Z INFO  alsa] ALSA lib confmisc.c:855:(parse_card) cannot find card '$CARD'
[2025-10-16T22:38:51Z INFO  alsa] ALSA lib conf.c:5205:(_snd_config_evaluate) function snd_func_card_inum returned error: No such device
[2025-10-16T22:38:51Z INFO  alsa] ALSA lib confmisc.c:422:(snd_func_concat) error evaluating strings
[2025-10-16T22:38:51Z INFO  alsa] ALSA lib conf.c:5205:(_snd_config_evaluate) function snd_func_concat returned error: No such device
[2025-10-16T22:38:51Z INFO  alsa] ALSA lib confmisc.c:1342:(snd_func_refer) error evaluating name
[2025-10-16T22:38:51Z INFO  alsa] ALSA lib conf.c:5205:(_snd_config_evaluate) function snd_func_refer returned error: No such device
[2025-10-16T22:38:51Z INFO  alsa] ALSA lib conf.c:5728:(snd_config_expand) Evaluate error: No such device
[2025-10-16T22:38:51Z INFO  alsa] ALSA lib conf.c:5541:(parse_args) Unknown parameter CARD
[2025-10-16T22:38:51Z INFO  alsa] ALSA lib conf.c:5712:(snd_config_expand) Parse arguments error: No such file or directory
[2025-10-16T22:38:51Z INFO  alsa] ALSA lib conf.c:5541:(parse_args) Unknown parameter CARD
...

This is due to trying to open devices that were configured as templates in ALSA. Basically this is an ALSA configuration mistake, however, there's no point to cpal trying to open them either, so that's just removed now.

Cleaned up a little while there.

This PR builds on top of #1033, so review just the last commits to see what's changed on top.

[roderickvd]

Note to self: devices() currently returns an empty Vec. Instead, it should return the combination of input and output devices.