feat: support image height in markdown rendering of messages (#8177)

- This PR adds BaseMarkdownRenderer, it takes all the required attributes from the image node, parses the cw_image_height query and renders it.

lib/base_markdown_renderer.rb

@@ -0,0 +1,39 @@
+class BaseMarkdownRenderer < CommonMarker::HtmlRenderer
+  def image(node)
+    src, title = extract_img_attributes(node)
+    height = extract_image_height(src)
+
+    render_img_tag(src, title, height)
+  end
+
+  private
+
+  def extract_img_attributes(node)
+    [
+      escape_href(node.url),
+      escape_html(node.title)
+    ]
+  end
+
+  def extract_image_height(src)
+    query_params = parse_query_params(src)
+    query_params['cw_image_height']&.first
+  end
+
+  def parse_query_params(url)
+    parsed_url = URI.parse(url)
+    CGI.parse(parsed_url.query || '')
+  rescue URI::InvalidURIError
+    {}
+  end
+
+  def render_img_tag(src, title, height = nil)
+    title_attribute = title.present? ? " title=\"#{title}\"" : ''
+    height_attribute = height ? " height=\"#{height}\" width=\"auto\"" : ''
+
+    plain do
+      # plain ensures that the content is not wrapped in a paragraph tag
+      out("<img src=\"#{src}\"#{title_attribute}#{height_attribute} />")
+    end
+  end
+end