Gracefully handle integer UV channels during GLB export

* Resolves #1811

Source/AssetRipper.SourceGenerated.Extensions/MeshData.cs

@@ -185,6 +185,6 @@ public readonly record struct MeshData(
 	[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
 	private static T TryGetAtIndex<T>(T[]? array, uint index) where T : struct
 	{
-		return array is null ? default : array[index];
+		return array is null or { Length: 0 } ? default : array[index];
 	}
 }

Source/AssetRipper.Tests/MeshDataTests.cs

@@ -0,0 +1,32 @@
+using AssetRipper.SourceGenerated.Extensions;
+
+namespace AssetRipper.Tests;
+
+internal class MeshDataTests
+{
+	[Test]
+	public void AccessingNullUV2DoesNotThrow()
+	{
+		MeshData meshData = MeshData.CreateTriangleMesh() with
+		{
+			UV2 = null
+		};
+		Assert.DoesNotThrow(() =>
+		{
+			meshData.TryGetUV2AtIndex(0);
+		});
+	}
+
+	[Test]
+	public void AccessingEmptyUV2DoesNotThrow()
+	{
+		MeshData meshData = MeshData.CreateTriangleMesh() with
+		{
+			UV2 = []
+		};
+		Assert.DoesNotThrow(() =>
+		{
+			meshData.TryGetUV2AtIndex(0);
+		});
+	}
+}