DEV: Remove superfluous js: true metadata (#21960)

Why this change?

It is very unlikely that we need to ever JS for system tests considering
that we rely on a JS framework on the frontend.

spec/system/composer/category_templates_spec.rb

@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-describe "Composer Form Templates", type: :system, js: true do
+describe "Composer Form Templates", type: :system do
   fab!(:user) { Fabricate(:user) }
   fab!(:form_template_1) do
     Fabricate(:form_template, name: "Bug Reports", template: "- type: checkbox")

spec/system/composer/default_to_subcategory_spec.rb

@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
-describe "Default to Subcategory when parent Category doesn't allow posting",
-         type: :system,
-         js: true do
+describe "Default to Subcategory when parent Category doesn't allow posting", type: :system do
   fab!(:user) { Fabricate(:user) }
   fab!(:group) { Fabricate(:group) }
   fab!(:group_user) { Fabricate(:group_user, user: user, group: group) }

spec/system/composer/dont_feed_the_trolls_popup_spec.rb

@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-describe "Composer don't feed the trolls popup", type: :system, js: true do
+describe "Composer don't feed the trolls popup", type: :system do
   fab!(:user) { Fabricate(:user) }
   fab!(:troll) { Fabricate(:user) }
   fab!(:topic) { Fabricate(:topic, user: user) }

spec/system/composer/review_media_unless_trust_level_spec.rb

@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-describe "Composer using review_media", type: :system, js: true do
+describe "Composer using review_media", type: :system do
   fab!(:user) { Fabricate(:user) }
   fab!(:topic) { Fabricate(:topic, category: Category.find(SiteSetting.uncategorized_category_id)) }
   fab!(:post) { Fabricate(:post, topic: topic) }