Drop required properties syntax

Sometimes, seemingly after random unrelated changes, it might stop
compiling with internal compiler error messages about missing features
and attributes. .NET Standard 2.1 is not supposed to support any
features beyond C# 8.0, while `required` attribute was introduced only
in C# 11 or 12, it's hard to tell.

MuzikaGromche/Plugin.cs

@@ -932,8 +932,8 @@ namespace MuzikaGromche
     // Suitable to declare elemnents of SelectableTracksGroup and as a base for standalone selectable tracks.
     public class CoreAudioTrack : IAudioTrack
     {
-        public required string Name { get; init; }
-        public required float WindUpTimer { get; init; }
+        public /* required */ string Name { get; init; } = "";
+        public /* required */ float WindUpTimer { get; init; } = 0f;
         public int Beats { get; init; }
 
         // Shorthand for four beats
@@ -1006,7 +1006,7 @@ namespace MuzikaGromche
     // Standalone, top-level, selectable audio track
     public class SelectableAudioTrack : CoreAudioTrack, ISelectableTrack
     {
-        public required Language Language { get; init; }
+        public /* required */ Language Language { get; init; }
         public bool IsExplicit { get; init; } = false;
         ConfigEntry<int> ISelectableTrack.Weight { get; set; } = null!;
 
@@ -1022,12 +1022,12 @@ namespace MuzikaGromche
 
     public class SelectableTracksGroup : ISelectableTrack
     {
-        public required string Name { get; init; }
-        public required Language Language { get; init; }
+        public /* required */ string Name { get; init; } = "";
+        public /* required */ Language Language { get; init; }
         public bool IsExplicit { get; init; } = false;
         ConfigEntry<int> ISelectableTrack.Weight { get; set; } = null!;
 
-        public required IAudioTrack[] Tracks;
+        public /* required */ IAudioTrack[] Tracks = [];
 
         IAudioTrack[] ISelectableTrack.GetTracks() => Tracks;
 
@@ -2393,9 +2393,9 @@ namespace MuzikaGromche
 
         class State
         {
-            public required int currentBehaviourStateIndex;
-            public required int previousState;
-            public required float stunNormalizedTimer;
+            public int currentBehaviourStateIndex;
+            public int previousState;
+            public float stunNormalizedTimer;
         }
 
         [HarmonyPatch(nameof(JesterAI.Update))]