Fixed looped audio playback position calculation

[ThereDrD0]

I encountered an odd bug: if I go far away from a looped audio source and return, the audio stops playing on the client. Disconnecting and reconnecting restores playback.

I figured out that it was a bug with the playback position calculation. It didn't account for the Loop parameter correctly and stopped playing because the position exceeded the audio length.

Here is a fix. + clean up redundant code and unused usings

Tests

Example

Before(master)

2025-12-24.22-13-05.mp4

After(my branch)

2025-12-24.22-09-49.mp4

Example code used to reproduce bug

using Robust.Server.Audio;

namespace Content.Server.AAA;

public sealed class TestSoundSystem : EntitySystem
{
    [Dependency] private readonly AudioSystem _audio = default!;

    public override void Initialize()
    {
        base.Initialize();

        SubscribeLocalEvent<TestSoundComponent, MapInitEvent>(OnMapInit);
    }

    private void OnMapInit(Entity<TestSoundComponent> ent, ref MapInitEvent args)
    {
        _audio.PlayPvs(ent.Comp.Sound, ent);
    }
}

using Robust.Shared.Audio;

namespace Content.Server.AAA;

[RegisterComponent]
public sealed partial class TestSoundComponent : Component
{
    [DataField]
    public SoundSpecifier Sound = new SoundPathSpecifier("/Audio/Effects/glass_break1.ogg",
        AudioParams.Default.WithMaxDistance(30f).WithVolume(10f).WithLoop(true));
}

[PJB3005]

Do not copy paste this code around everywhere

[ThereDrD0]

Hey, just wondering if this is good to go?