Cleanup code

Author: ScarletKuro

src/Scarlet.System.Text.Json.DateTimeConverter/Converters/DateOnlyNullableConverter.cs

@@ -26,11 +26,6 @@ internal sealed class DateOnlyNullableConverter : JsonConverter<DateOnly?>
     /// <returns>The converted nullable <see cref="DateOnly"/> object, or null if the JSON token is null.</returns>
     public override DateOnly? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
     {
-        if (reader.TokenType == JsonTokenType.Null)
-        {
-            return null;
-        }
-
         if (reader.TokenType == JsonTokenType.String)
         {
             if (DateOnly.TryParseExact(reader.GetString(), _format, CultureInfo.InvariantCulture, DateTimeStyles.None, out DateOnly date))

src/Scarlet.System.Text.Json.DateTimeConverter/Converters/DateTimeNullableConverter.cs

@@ -26,11 +26,6 @@ internal sealed class DateTimeNullableConverter : JsonConverter<DateTime?>
     /// <returns>The converted nullable <see cref="DateTime"/> object, or null if the JSON token is null.</returns>
     public override DateTime? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
     {
-        if (reader.TokenType == JsonTokenType.Null)
-        {
-            return null;
-        }
-
         if (reader.TokenType == JsonTokenType.String)
         {
             if (DateTime.TryParseExact(reader.GetString(), _format, CultureInfo.InvariantCulture, DateTimeStyles.None, out DateTime date))

src/Scarlet.System.Text.Json.DateTimeConverter/Converters/DateTimeOffsetNullableConverter.cs

@@ -26,11 +26,6 @@ internal sealed class DateTimeOffsetNullableConverter : JsonConverter<DateTimeOf
     /// <returns>The converted nullable <see cref="DateTimeOffset"/> object, or null if the JSON token is null.</returns>
     public override DateTimeOffset? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
     {
-        if (reader.TokenType == JsonTokenType.Null)
-        {
-            return null;
-        }
-
         if (reader.TokenType == JsonTokenType.String)
         {
             if (DateTimeOffset.TryParseExact(reader.GetString(), _format, CultureInfo.InvariantCulture, DateTimeStyles.None, out DateTimeOffset date))

src/Scarlet.System.Text.Json.DateTimeConverter/Converters/TimeOnlyNullableConverter.cs

@@ -26,11 +26,6 @@ internal sealed class TimeOnlyNullableConverter : JsonConverter<TimeOnly?>
     /// <returns>The converted nullable <see cref="TimeOnly"/> object, or null if the JSON token is null.</returns>
     public override TimeOnly? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
     {
-        if (reader.TokenType == JsonTokenType.Null)
-        {
-            return null;
-        }
-
         if (reader.TokenType == JsonTokenType.String)
         {
             if (TimeOnly.TryParseExact(reader.GetString(), _format, CultureInfo.InvariantCulture, DateTimeStyles.None, out TimeOnly time))