Remove duplicate DataRow attributes in unit tests

Eliminated repeated [DataRow(64, 4, 0)] attributes from three test methods in Test_MemoryExtensions.cs to avoid redundant test cases and improve test clarity.

Author: Sergio0694

tests/CommunityToolkit.HighPerformance.UnitTests/Extensions/Test_MemoryExtensions.cs

@@ -430,7 +430,6 @@ public void Test_MemoryExtensions_FromMemoryManager_CastFromByteAndBack_WithSlic
     [DataRow(64, 4, 0)]
     [DataRow(64, 0, 4)]
     [DataRow(64, 4, 4)]
-    [DataRow(64, 4, 0)]
     [DataRow(256, 16, 0)]
     [DataRow(256, 4, 16)]
     [DataRow(256, 64, 0)]
@@ -460,7 +459,6 @@ public unsafe void Test_MemoryExtensions_FromArray_CastFromByte_Pin(int size, in
     [DataRow(64, 4, 0)]
     [DataRow(64, 0, 4)]
     [DataRow(64, 4, 4)]
-    [DataRow(64, 4, 0)]
     [DataRow(256, 16, 0)]
     [DataRow(256, 4, 16)]
     [DataRow(256, 64, 0)]
@@ -511,7 +509,6 @@ public void Test_MemoryExtensions_FromString_CastFromByteAndBack()
     [DataRow(64, 4, 0)]
     [DataRow(64, 0, 4)]
     [DataRow(64, 4, 4)]
-    [DataRow(64, 4, 0)]
     [DataRow(256, 16, 0)]
     [DataRow(256, 4, 16)]
     [DataRow(256, 64, 0)]