Query language parameter in search endpoint should not have a default

Currently Swagger docs for

/api/v1/search/lang/{queryLanguage}/execute

flag "queryLanguage" as required with a default value of "NXQL", however, according to Swagger documentation

Using default with required parameters or properties, for example, with path parameters. This does not make sense — if a value is required, the client must always send it, and the default value is never used.

So default value should be removed.