fix: update lax BooleanDrop expected value to match StandardBooleanDrop

[tobi]

Problem

liquid-spec 2.0.0 loads standard_drops.rb after liquid_ruby.rb (line 613), so instantiate:BooleanDrop now creates StandardBooleanDrop (to_s → "true"/"false") instead of the legacy BooleanDrop (to_s → "Yay"/"Nay").

The non-lax liquid_ruby/variable_type_filters.yml was already updated to expect "true", but the lax version (liquid_ruby_lax/variable_type_filters.yml) was missed — it still expects "Yay".

Confirmation

Reference liquid (Shopify/liquid) also renders "true":

require "liquid"
require "liquid/spec/deps/liquid_ruby"
f = Liquid::Spec::ClassRegistry.all["BooleanDrop"]
d = f.call({"value" => true})
Liquid::Template.parse("{{ d }}").render({"d" => d})
# => "true"

Fix

2-line change: update the hint and expected value to match StandardBooleanDrop behavior, consistent with the non-lax suite.