test: remove unnecessary stubbing

Author: grzuy

spec/webauthn/authenticator_attestation_response_spec.rb

@@ -258,11 +258,6 @@
 
     before do
       allow(attestation_response.attestation_statement).to receive(:time).and_return(time)
-      allow(attestation_response).to receive(:attestation_root_certificates_store).and_wrap_original do |m, *args|
-        store = m.call(*args)
-        store.time = time
-        store
-      end
     end
 
     it "verifies" do