Add error messaging for if a file fails to download

[drewjenkins]

Description and Context

Fixes #450

This was a bit tricky to repro, but I was able to do so by manually failing the request by manipulating my wifi via a script like

const { exec } = require('child_process');

exec('rm -rf temp/images', () => {
  console.log('removed');

  console.log('starting fetch');
  exec(
    './node_modules/.bin/hs fetch modules temp/images',
    (err, stdout, stderr) => {
      console.log(stdout, stderr);
      console.log('completed fetch');
      exec('networksetup -setairportpower Wi-Fi on', () => {
        console.log('wifi turned on');
      });
    }
  );

  setTimeout(() => {
    console.log('turning off wifi');
    exec('networksetup -setairportpower Wi-Fi off', () => {
      console.log('wifi turned off');
    });
  }, 1300);
});

With this fix, we will now show an error message instead of a success message if any of the files fails to download

[brandenrodgers]

This lgtm 👍 Just two questions

Does logFileSystemErrorInstance not log the errors (in writeFileMapperNode)?
Also, could you post a screenshot of what the failed state looks like now?

[drewjenkins]

It logs the errors, but the whole operation is marked success as long as it completes, regardless if it has errors or not. And sure. My output is a bit different than above just cuz of how I was reproing, also it isnt colored cuz im running it thru a node script, but here

@brandenrodgers