Fixed regression caused by performance change (#51032)

- Pass empty array instead of null for validations

src/libraries/Microsoft.Extensions.Options/src/OptionsFactory.cs

@@ -25,7 +25,7 @@ public class OptionsFactory<[DynamicallyAccessedMembers(Options.DynamicallyAcces
         /// </summary>
         /// <param name="setups">The configuration actions to run.</param>
         /// <param name="postConfigures">The initialization actions to run.</param>
-        public OptionsFactory(IEnumerable<IConfigureOptions<TOptions>> setups, IEnumerable<IPostConfigureOptions<TOptions>> postConfigures) : this(setups, postConfigures, validations: null)
+        public OptionsFactory(IEnumerable<IConfigureOptions<TOptions>> setups, IEnumerable<IPostConfigureOptions<TOptions>> postConfigures) : this(setups, postConfigures, validations: Array.Empty<IValidateOptions<TOptions>>())
         { }
 
         /// <summary>

src/libraries/Microsoft.Extensions.Options/tests/Microsoft.Extensions.Options.Tests/OptionsFactoryTests.cs

@@ -168,6 +168,15 @@ public void CanPostConfigureAllDefaultAndNamedOptions()
             Assert.Equal("Default1", factory.Create("1").Message);
         }
 
+        [Fact]
+        public void CanCreateOptionsFactory()
+        {
+            var factory = new OptionsFactory<FakeOptions>(new IConfigureOptions<FakeOptions>[0],
+                new IPostConfigureOptions<FakeOptions>[] { });
+            
+            Assert.Equal("", factory.Create("").Message);
+        }
+
         public class FakeOptionsSetupA : ConfigureOptions<FakeOptions>
         {
             public FakeOptionsSetupA() : base(o => o.Message += "A") { }