Put sync detail detection mediastore behind feature flag (forem#21231)

* Put sync detail detection mediastore behind feature flag

* Content safe traversal

app/lib/redcarpet/render/html_rouge.rb

@@ -26,9 +26,9 @@ def image(link, title, alt_text)
         end
       end
 
-      def link(link, _title, content)
+      def link(link, _title, content) # rubocop:disable Metrics/PerceivedComplexity
         # Regex to capture src, alt, and title attributes from an img tag
-        if content.include?("<img") && (doc = Nokogiri::HTML(content))
+        if content&.include?("<img") && (doc = Nokogiri::HTML(content))
           image_url = doc.at_css("img")["src"]
           alt_text = doc.at_css("img")["alt"] || nil
           title = doc.at_css("img")["title"] || nil

app/services/content_renderer.rb

@@ -24,7 +24,7 @@ def initialize(input, source: nil, user: nil, fixer: MarkdownProcessor::Fixer::F
   # @return [ContentRenderer::Result]
   def process(link_attributes: {},
               prefix_images_options: { width: 800, synchronous_detail_detection: false })
-    if prefix_images_options[:synchronous_detail_detection] && ApplicationConfig["AWS_BUCKET_NAME"].present?
+    if prefix_images_options[:synchronous_detail_detection] && ApplicationConfig["AWS_BUCKET_NAME"].present? && FeatureFlag.enabled?(:store_images) # rubocop:disable Layout/LineLength
       markdown_text = input
       markdown_pattern = /!\[.*?\]\((.*?)\)/
       html_pattern = /<img.*?src=["'](.*?)["']/