AfterCommitOverride fails with lambda param

[gaffneyc]

Expected behavior

AfterCommitOverride should ignore lambda or block arguments and not error. The cop is supposed to only check that a given method isn't defined in multiple after_commit hooks as only the last definition will be used. One way to get around this is to instead pass a lambda which will call the method. Unfortunately that causes the cop to error.

Actual behavior

RuboCop errors with the below (truncated) stack:

undefined method `value' for #<RuboCop::AST::BlockNode:0x00007f7dee922ef8>
rubocop-rails-2.8.0/lib/rubocop/cop/rails/after_commit_override.rb:49:in `block in on_class'
rubocop-rails-2.8.0/lib/rubocop/cop/rails/after_commit_override.rb:62:in `block in each_after_commit_callback'
rubocop-rails-2.8.0/lib/rubocop/cop/rails/after_commit_override.rb:61:in `each'
rubocop-rails-2.8.0/lib/rubocop/cop/rails/after_commit_override.rb:61:in `each_after_commit_callback'
rubocop-rails-2.8.0/lib/rubocop/cop/rails/after_commit_override.rb:48:in `on_class'

Steps to reproduce the problem

class Fake < ActiveRecord::Base
  after_commit -> { foo }

  def foo
  end
end

rubocop -d -o Rails/AfterCommitOverride app/models/fake.rb

RuboCop version

0.90.0 (using Parser 2.7.1.4, rubocop-ast 0.3.0, running on ruby 2.7.1 x86_64-linux)