[filesapp] Skip looking for SVG images in "2x" sub-directories

The ui/file_manager/file_manager/foreground/images directory contains
the files app icons, including icons used by {Audio,Video} player and
the Gallery extension.

Update the local generate_image_html.sh script to look for SVG in the
root sub-directories only: not the 2x sub-directories since they only
contain "2x" PNG images. SVG images do not need / have "2x" variants.

No-try: true
Bug: files-app-icon-health
Change-Id: I278d34cb5c2a7208b02f3fbd84248bbae028f584
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2599575Reviewed-by: Noel Gordon <noel@chromium.org>
Reviewed-by: Alex Danilo <adanilo@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#839041}

ui/file_manager/file_manager/foreground/images/generate_image_html.sh

@@ -61,6 +61,11 @@ for directory in $(find_directories_containing_images); do
     output_html_image_element "${directory}/${image}" PNG
   done ; echo "</p>"
 
+  # There are no SVG images in the "2x" sub-directories.
+  if grep -q "/2x" <<< "${directory}"; then
+    continue
+  fi
+
   # generate HTML for the directory SVG images.
   echo "<h4>sub-directory ${directory} SVG images</h4><p>"
   ls ${directory} | grep -e "\.svg$" | while read image; do