Revert "FEATURE: Introduce theme/component QUnit tests (#12517)" (#12632)

This reverts commit a53d8d3e61 and 105634435f.

Reverted because the change broke some components. Will be added back in a few days.

app/controllers/theme_javascripts_controller.rb

@@ -8,7 +8,7 @@ class ThemeJavascriptsController < ApplicationController
     :preload_json,
     :redirect_to_login_if_required,
     :verify_authenticity_token,
-    only: [:show, :show_tests]
+    only: [:show]
   )
 
   before_action :is_asset_path, :no_cookies, :apply_cdn_headers, only: [:show]
@@ -34,29 +34,6 @@ class ThemeJavascriptsController < ApplicationController
     send_file(cache_file, disposition: :inline)
   end
 
-  def show_tests
-    raise Discourse::NotFound if Rails.env.production?
-
-    theme_id = params.require(:theme_id)
-    theme = Theme.find(theme_id)
-    content = ThemeField
-      .where(
-        theme_id: theme_id,
-        target_id: Theme.targets[:tests_js]
-      )
-      .each(&:ensure_baked!)
-      .map(&:value_baked)
-      .join("\n")
-
-    ThemeJavascriptCompiler.force_default_settings(content, theme)
-
-    response.headers["Content-Length"] = content.size.to_s
-    response.headers["Last-Modified"] = Time.zone.now.httpdate
-    immutable_for(1.second)
-
-    send_data content, filename: "js-tests-theme-#{theme_id}.js", disposition: :inline
-  end
-
   private
 
   def query