Simplify tests replying to a comment

We were using the `reply_to` method in some places, but not in others.

spec/shared/system/notifiable_in_app.rb

@@ -51,18 +51,7 @@ shared_examples "notifiable in-app" do |factory_name|
   scenario "A user replied to my comment" do
     comment = create(:comment, commentable: notifiable, user: author)
 
-    login_as(create(:user, :verified))
-    visit path_for(notifiable)
-
-    click_link "Reply"
-    within "#js-comment-form-comment_#{comment.id}" do
-      fill_in comment_body(notifiable), with: "I replied to your comment"
-      click_button "Publish reply"
-    end
-
-    within "#comment_#{comment.id}" do
-      expect(page).to have_content "I replied to your comment"
-    end
+    reply_to(comment, with: "I replied to your comment", replier: create(:user, :verified))
 
     logout
     login_as author
@@ -120,18 +109,7 @@ shared_examples "notifiable in-app" do |factory_name|
   scenario "Author replied to his own comment" do
     comment = create(:comment, commentable: notifiable, user: author)
 
-    login_as author
-    visit path_for(notifiable)
-
-    click_link "Reply"
-    within "#js-comment-form-comment_#{comment.id}" do
-      fill_in comment_body(notifiable), with: "I replied to my own comment"
-      click_button "Publish reply"
-    end
-
-    within "#comment_#{comment.id}" do
-      expect(page).to have_content "I replied to my own comment"
-    end
+    reply_to(comment, with: "I replied to my own comment", replier: author)
 
     within("#notifications") do
       click_link "You don't have new notifications"

spec/support/common_actions/comments.rb

@@ -4,11 +4,17 @@ module Comments
 
     visit polymorphic_path(comment.commentable)
 
-    click_link "Reply"
+    within "#comment_#{comment.id}" do
+      click_link "Reply"
+    end
+
     within "#js-comment-form-comment_#{comment.id}" do
-      fill_in "Leave your comment", with: with
+      fill_in comment_body(comment.commentable), with: with
       click_button "Publish reply"
     end
-    expect(page).to have_content with
+
+    within "#comment_#{comment.id}" do
+      expect(page).to have_content with
+    end
   end
 end

spec/system/comments_spec.rb

@@ -383,21 +383,7 @@ describe "Comments" do
   scenario "Reply" do
     comment = create(:comment, commentable: resource)
 
-    login_as(user)
-    visit polymorphic_path(resource)
-
-    within "#comment_#{comment.id}" do
-      click_link "Reply"
-    end
-
-    within "#js-comment-form-comment_#{comment.id}" do
-      fill_in fill_text, with: "It will be done next week."
-      click_button "Publish reply"
-    end
-
-    within "#comment_#{comment.id}" do
-      expect(page).to have_content "It will be done next week."
-    end
+    reply_to(comment, with: "It will be done next week.", replier: user)
 
     expect(page).not_to have_css "#js-comment-form-comment_#{comment.id}"
   end