Remove redundant setting resets in after blocks

Settings are stored in the database, and so any changes to the settings
done during the tests are automatically rolled back between one test and
the next one.

There were also a few places where we weren't using an `after` block but
changing the setting at the end of the test.

spec/features/admin/budget_groups_spec.rb

@@ -20,10 +20,6 @@ describe "Admin budget groups" do
       Setting["process.budgets"] = nil
     end
 
-    after do
-      Setting["process.budgets"] = true
-    end
-
     scenario "Disabled with a feature flag" do
       expect do
         visit admin_budget_groups_path(budget)

spec/features/admin/budget_headings_spec.rb

@@ -21,10 +21,6 @@ describe "Admin budget headings" do
       Setting["process.budgets"] = nil
     end
 
-    after do
-      Setting["process.budgets"] = true
-    end
-
     scenario "Disabled with a feature flag" do
       expect do
         visit admin_budget_group_headings_path(budget, group)

spec/features/admin/budget_investments_spec.rb

@@ -28,10 +28,6 @@ describe "Admin budget investments" do
       Setting["process.budgets"] = nil
     end
 
-    after do
-      Setting["process.budgets"] = true
-    end
-
     scenario "Disabled with a feature flag" do
       expect { visit admin_budgets_path }.to raise_exception(FeatureFlags::FeatureDisabled)
     end

spec/features/admin/debates_spec.rb

@@ -8,8 +8,6 @@ describe "Admin debates" do
     login_as(admin.user)
 
     expect { visit admin_hidden_debates_path }.to raise_exception(FeatureFlags::FeatureDisabled)
-
-    Setting["process.debates"] = true
   end
 
   before do

spec/features/admin/legislation/processes_spec.rb

@@ -287,7 +287,6 @@ describe "Admin collaborative legislation" do
     let!(:process) { create(:legislation_process) }
 
     before { Setting["feature.translation_interface"] = true }
-    after { Setting["feature.translation_interface"] = nil }
 
     scenario "Cant manage translations on homepage form" do
       visit edit_admin_legislation_process_homepage_path(process)

spec/features/admin/settings_spec.rb

@@ -138,10 +138,6 @@ describe "Admin settings" do
       Setting["feature.remote_census"] = true
     end
 
-    after do
-      Setting["feature.remote_census"] = nil
-    end
-
     scenario "Should not be able when remote census feature deactivated" do
       Setting["feature.remote_census"] = nil
       admin = create(:administrator).user
@@ -178,10 +174,6 @@ describe "Admin settings" do
         Setting["feature.remote_census"] = true
       end
 
-      after do
-        Setting["feature.remote_census"] = nil
-      end
-
       scenario "On #tab-remote-census-configuration", :js do
         remote_census_setting = create(:setting, key: "remote_census.general.whatever")
         admin = create(:administrator).user
@@ -221,10 +213,6 @@ describe "Admin settings" do
         Setting["feature.map"] = true
       end
 
-      after do
-        Setting["feature.map"] = nil
-      end
-
       scenario "On #tab-map-configuration", :js do
         map_setting = Setting.create(key: "map.whatever")
         admin = create(:administrator).user

spec/features/admin/signature_sheets_spec.rb

@@ -89,12 +89,6 @@ describe "Signature sheets" do
       Setting["remote_census.response.valid"] = access_user_data
     end
 
-    after do
-      Setting["feature.remote_census"] = nil
-      Setting["remote_census.request.date_of_birth"] = nil
-      Setting["remote_census.request.postal_code"] = nil
-    end
-
     scenario "Proposal" do
       proposal = create(:proposal)
       visit new_admin_signature_sheet_path