Aot remove reflection - #977

Dereference of a possibly null reference.

Possible null reference argument for parameter 'attachment' in 'Attachment? AttachmentSerializer.Deserialize(string attachment)'.

Possible null reference argument for parameter 'item' in 'bool HashSet<string>.Add(string item)'.

Possible null reference argument for parameter 'factory' in 'void RecurrenceRuleSerializer.DeserializeRule(string value, RecurrenceRule r, ISerializerFactory factory)'.

Possible null reference argument for parameter 'dt' in 'string? EncodableDataTypeSerializer.Decode(IEncodableDataType dt, string value)'.

Dereference of a possibly null reference.

Possible null reference argument for parameter 'item' in 'bool HashSet<string>.Contains(string item)'.

Dereference of a possibly null reference.

Possible null reference argument for parameter 'attachment' in 'Attachment? AttachmentSerializer.Deserialize(string attachment)'.