fix nvidia troubleshooting on arm64 (#2508)

ErsatzTV.FFmpeg/Capabilities/Nvidia/CudaHelper.cs

@@ -8,6 +8,8 @@ namespace ErsatzTV.FFmpeg.Capabilities.Nvidia;
 
 internal static class CudaHelper
 {
+    public static bool IsLoaded { get; set; }
+
     private static bool _success;
     private static bool _initialized;
     private static readonly Lock Lock = new();
@@ -82,7 +84,7 @@ internal static class CudaHelper
     {
         var result = new List<CudaDevice>();
 
-        if (!EnsureInit())
+        if (!IsLoaded || !EnsureInit())
         {
             return Option<List<CudaDevice>>.None;
         }

ErsatzTV.FFmpeg/Capabilities/Nvidia/NvEncSharpRedirector.cs

@@ -7,7 +7,15 @@ public static class NvEncSharpRedirector
 {
     static NvEncSharpRedirector()
     {
-        NativeLibrary.SetDllImportResolver(typeof(Lennox.NvEncSharp.LibCuda).Assembly, Resolver);
+        try
+        {
+            NativeLibrary.SetDllImportResolver(typeof(Lennox.NvEncSharp.LibCuda).Assembly, Resolver);
+            CudaHelper.IsLoaded = true;
+        }
+        catch (FileNotFoundException)
+        {
+            CudaHelper.IsLoaded = false;
+        }
     }
 
     private static IntPtr Resolver(string libraryName, Assembly assembly, DllImportSearchPath? searchPath)