feat: expose a layer value

[cyhoon]

Changes

I want to use a Layer's value :)

[vijaye-statsig]

@tore-statsig @daniel-statsig

[tore-statsig]

Unlike experiments and feature gates, when you call getLayer, we do not automatically log an exposure.

Exposures are logged at the parameter level, so when you get a parameter, it triggers an exposure log. If we open this up like this, its too error prone to mess up your exposure logging.

Whats your use case for this? Can you get each parameter instead?