Use SYLT tag for synchronized lyrics

[thomas-mc-work]

Currently the lyrics plugin has the option synced:

synced: Prefer synced lyrics over plain lyrics if a source offers them. Currently lrclib is the only source that provides them.

The results are written into the USLT tag though. While this is correct for unsynchronized lyrics it's not for synchronized as the specification tells:

https://id3.org/id3v2.3.0#sec4.10

It would be great if the plugin would choose the correct tag/field (SYLT) depending on the synced modifier (or finally not the modifier itself but based on what it could fetch, since the modifier isn't enforcing but only requesting).