[fuchsia] Update local-sdk script with missing build target.

Change-Id: I172fb7f98693cd2b8e46b7510b9160b4e49cdae2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1733854
Commit-Queue: Fabrice de Gans-Riberi <fdegans@chromium.org>
Commit-Queue: Kevin Marshall <kmarshall@chromium.org>
Auto-Submit: Fabrice de Gans-Riberi <fdegans@chromium.org>
Reviewed-by: Kevin Marshall <kmarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#683741}

tools/fuchsia/local-sdk.py

@@ -37,7 +37,8 @@ def BuildForArch(arch):
   Run('scripts/fx', '--dir', build_dir, 'set', 'terminal.qemu-'+ arch,
       '--with=//topaz/packages/sdk:topaz', '--with-base=//sdk/bundles:tools',
       '--args=is_debug=false', '--args=build_sdk_archives=true')
-  Run('scripts/fx', 'build', 'topaz/public/sdk:fuchsia_dart', 'sdk')
+  Run('scripts/fx', 'build', 'topaz/public/sdk:fuchsia_dart', 'sdk',
+      'build/images')
 
 
 def main(args):