Hydrated `BaseModels` do not correctly work with `Update` and `Delete`

[acupofjose]

BaseUrl, RequestClientOptions and GetHeaders are net set on hydrated models supplied by the realtime-csharp client. Because these are unset, Update and Delete calls on a hydrated BaseModel will fail.

See here the following lines: https://github.com/supabase-community/postgrest-csharp/blob/64525d49ae7c066bd38fdbd3b6c95593346e0369/Postgrest/Models/BaseModel.cs#L19-L26