Prevent NoMethodError in extract_value when specifying non-existent keys

Introduced in rails#49042, the method `ActionController::Parameters#extract_value` promises to replace utility methods that were previously defined as private methods in controllers.
However, it currently throws a `NoMethodError` when passed a non-existent key.

`params` is dependent on client requests and is thus beyond the application's control.
Rather than throwing a `NoMethodError`, it would be more convenient for the method to return `nil`.

Author: euglena1215

actionpack/lib/action_controller/metal/strong_parameters.rb

@@ -931,8 +931,9 @@ def deep_dup
     #   params = ActionController::Parameters.new(id: "1_123", tags: "ruby,rails")
     #   params.extract_value(:id) # => ["1", "123"]
     #   params.extract_value(:tags, delimiter: ",") # => ["ruby", "rails"]
+    #   params.extract_value(:non_existent_key) # => nil
     def extract_value(key, delimiter: "_")
-      @parameters[key].split(delimiter)
+      @parameters[key]&.split(delimiter)
     end
 
     protected

actionpack/test/controller/parameters/accessors_test.rb

@@ -430,5 +430,6 @@ class ParametersAccessorsTest < ActiveSupport::TestCase
 
     assert_equal(["1", "123"], params.extract_value(:id))
     assert_equal(["ruby", "rails", "web"], params.extract_value(:tags, delimiter: ","))
+    assert_nil(params.extract_value(:non_existent_key))
   end
 end