Apply Style/MethodDefParentheses rubocop rule

This is an obvious one, but there was one place where we weren't
following it.

.rubocop.yml

@@ -388,6 +388,9 @@ Style/HashSyntax:
 Style/IdenticalConditionalBranches:
   Enabled: true
 
+Style/MethodDefParentheses:
+  Enabled: true
+
 Style/Not:
   Enabled: true
 

spec/features/admin/legislation/processes_spec.rb

@@ -157,7 +157,7 @@ describe "Admin collaborative legislation" do
     end
 
     scenario "Create a legislation process with an image", :js do
-      visit new_admin_legislation_process_path()
+      visit new_admin_legislation_process_path
       fill_in "Process Title", with: "An example legislation process"
       fill_in "Summary", with: "Summary of the process"