[Client bug]: EducationAssignment doesn't serialize assignDateTime

Describe the bug
When trying to patch the EducationAssignment.AssignDateTime via the graph service client, the value won't be set.

To Reproduce

        [Fact]
        public void EducationAssignmentSerializesAssignDateTime()
        {
            var tokenCredentials = Azure.Core.DelegatedTokenCredential.Create(null);
            var serviceClient = new GraphServiceClient(tokenCredentials);

            var source = new EducationAssignment
            {
                AssignDateTime = new DateTime(2023, 4, 13, 13, 45, 00),
            };

            var requestInfo = serviceClient
                .Education
                .Classes["classId"]
                .Assignments["assignmentId"]
                .ToPatchRequestInformation(source);

            var memory = new MemoryStream();
            requestInfo.Content.CopyTo(memory);
            var bytes = memory.ToArray();
            var json = Encoding.UTF8.GetString(bytes);

            // Currently json is only "{}"
            Assert.Contains("assignDateTime", json);
        }

Expected behavior
This property (and also some others) should be writeable via the SDK. According to the documenation this value is writeable (at least under specific conditions):

Date the assignment should be published to students. Cannot be edited after the assignment has been published.

But the current serialize code shows, that not all properties are written, that are read.

Workaround
Fortunately the bag AdditionalData can be misused to get the value back to graph, but this should be fixed ASAP:

source.AdditionalData["assignDateTime"] = source.AssignDateTime;

Client version
5.5.0

Additional context
Currently I just stumbled across this specific property, that is accidentially marked as read-only (or what is the reason, that this property can be deserialized, but not serialized?). And potentially someone from the education team has to review all meta information to ensure, that we won't find the next missing property after this one has been fixed and released.

Start in src/Microsoft.Graph/Generated/Models/EducationAssignment.cs, comparing the serialization code with the deserialization code for AssignDateTime. Use the reproduction test from the issue to verify the generated patch request content. Done means the request JSON contains assignDateTime and the regression test passes.