[ENHANCEMENT] [MODDING] QOL changes to strumlines

[AbnormalPoof]

Does this PR close any issues? If so, link them below.

Closes #2616

Briefly describe the issue(s) fixed.

This PR changes initStrumlines() so that it now takes a note style ID instead of a noteStyle, along with the option to disable the fade.
Additionally, changes were made so changing a strumline's notestyle mid-song is way easier! Just change noteStyleId and the graphics will be updates automatically. Technically you could already do this before but it was very inefficient:

pr.showcase.mp4

Code snippet:

if (PlayState.instance != null)
{
  if (FlxG.keys.justPressed.EIGHT)
  {
    pixelEnabled = !pixelEnabled;
    if (pixelEnabled)
    {
      PlayState.instance.playerStrumline.noteStyleId = 'pixel';
      PlayState.instance.opponentStrumline.noteStyleId = 'pixel';
    }
    else
    {
      PlayState.instance.playerStrumline.noteStyleId = 'funkin';
      PlayState.instance.opponentStrumline.noteStyleId = 'funkin';
    }
  }
}

This doesn't break note kinds that use another notestyle (here the notekind has the funkin notestyle):

it_works_fine.mp4

Include any relevant screenshots or videos.

erect.sampler.thing.mp4

Issues

• The sustain trail doesn't update if you are already holding it. I don't know how to fix it, sorry.

Please let me know if you encounter issues with this PR!! I only tested this with the pixel notestyle.
Also note that this will break mods that use initStrumlines().

[Lasercar]

There's one possible issue I see in this code - if a custom note kind sets a different style, then it might be overridden with this.

And it's just been tested and it doesn't override it so

[Lasercar]

I approve!

[EliteMasterEric]

This is pretty neato! A follow-up PR could include a SetNoteStyleSongEvent.