remove duplicate test

Author: mikeebowen

test/DocumentFormat.OpenXml.Tests/ofapiTest/OpenXmlElementTest2.cs

@@ -8,7 +8,6 @@
 using DocumentFormat.OpenXml.Wordprocessing;
 using System;
 using System.IO;
-using System.Xml;
 using Xunit;
 
 namespace DocumentFormat.OpenXml.Tests
@@ -198,21 +197,6 @@ public void CanSetNullValue()
             Assert.Null(cell.Child);
         }
 
-        /// <summary>
-        /// A test for OpenXmlElement.GetOrAddFirstChild.
-        /// </summary>
-        [Fact]
-        public void GetOrAddFirstChildTest()
-        {
-            Paragraph p = new();
-            Run r = p.GetOrAddFirstChild<Run>();
-            Assert.NotNull(r);
-            Assert.Same(r, p.GetFirstChild<Run>());
-
-            var r2 = p.GetOrAddFirstChild<Run>();
-            Assert.Same(r, r2);
-        }
-
         private class WithChildElement : OpenXmlCompositeElement
         {
             public ChildElement Child