Lazy invalid defaults get silently converted to nil

[tfausak]

I discovered that setting a default to a lazy value of the wrong type silently converts it to nil instead of raising an error. For example:

class Example < ActiveInteraction::Base
  boolean :a_boolean,
    default: -> { Object.new }

  def execute
    inputs
  end
end

Example.run!
# => {:a_boolean=>nil}

That should be raising an InvalidDefaultError, as it would when default: Object.new.

[AaronLasseigne]

:(

[tfausak]

I probably introduced this regression in #271.

[tfausak]

In particular, I think #271 and #265 conspired to create this regression.