Patch Devise::Test::ControllerHelpers#sign_in to sign-out first

Signed-off-by: Rémy Coutable <remy@rymai.me>

spec/support/helpers/controller_helpers.rb

+# frozen_string_literal: true
+
+module ControllerHelpers
+  # It seems Devise::Test::ControllerHelpers#sign_in doesn't clear out the @current_user
+  # variable of the controller, hence it's not overwritten on retries.
+  # This should be fixed in Devise:
+  #   - https://github.com/heartcombo/devise/issues/5190
+  #   - https://github.com/heartcombo/devise/pull/5191
+  def sign_in(resource, deprecated = nil, scope: nil)
+    super
+
+    scope ||= Devise::Mapping.find_scope!(resource)
+
+    @controller.instance_variable_set(:"@current_#{scope}", nil)
+  end
+end
+
+Devise::Test::ControllerHelpers.prepend(ControllerHelpers)