Correctly pass default or user-defined value of similarity threshold to LocalEmbedder for Smart ComboBox

[Mimisss]

Smart ComboBox always posts 5 (integer) as the value of similarity threshold. This prevents the MVC Razor Pages example to work properly (no suggestions are presented). The sample code is (quickly) fixed by getting the POSTed value of similarityThreshold parameter and converting it to float using the expected format provider.

Addresses #64 for the MVC Razor Pages sample code. #64 still needs to be fixed internally.