Make the group member APIs public (they weren't) and add tests for them.

Author: teo-tsirpanis

Diff for: sources/TileDB.CSharp/Group.cs

@@ -280,7 +280,7 @@ public ulong MemberCount()
         /// Get member by index.
         /// </summary>
         /// <param name="index">The member's index.</param>
-        (string uri, ObjectType object_type, string name) MemberByIndex(ulong index)
+        public (string Uri, ObjectType ObjectType, string Name) GetMemberByIndex(ulong index)
         {
             using var ctxHandle = _ctx.Handle.Acquire();
             using var handle = _handle.Acquire();
@@ -299,7 +299,7 @@ public ulong MemberCount()
         /// Get member by name.
         /// </summary>
         /// <param name="name">The member's name.</param>
-        (string uri, ObjectType object_type) MemberByName(string name)
+        public (string Uri, ObjectType ObjectType) GetMemberByName(string name)
         {
             using var ctxHandle = _ctx.Handle.Acquire();
             using var handle = _handle.Acquire();

Diff for: tests/TileDB.CSharp.Test/GroupTest.cs

@@ -73,6 +73,8 @@ public void TestGroupMember()
             //Reopen in read mode
             group1.Open(QueryType.Read);
             Assert.AreEqual<ulong>(2, group1.MemberCount());
+            Assert.AreEqual("array1", group1.GetMemberByIndex(0).Name);
+            Assert.AreEqual(ObjectType.Array, group1.GetMemberByName("array2").ObjectType);
             group1.Close();
 
             //Reopen in write mode