Fix mini-browser-endpoint missing resource response

[DoroNahari]

Signed-off-by: Doron Nahari doron.nahari@sap.com

What it does

Fix mini-browser-endpoint missing resource response.
When requiring a resource from the mini-browser such as <theia-url>/mini-browser/<path-to-resource>
it returns:

And after this fix:

How to test

• Run Theia locally.
• Open browser dev-tools and go to network tab.
• Enter this url in the browser:
  localhost:3000/mini-browser/<path-to-resource-non-existing-resource>

Before the fix you'll get 200 response code and with the fix you'll get 404

Review checklist

• as an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• as a reviewer, I agree to behave in accordance with the review guidelines

[vince-fugnitto]

@DoroNahari please include a how to test for reviewers (so they can easily verify the changes).

[paul-marechal]

LGTM, just replaced send with sendStatus because it is the recommended API.

[amiramw]

Tested successfully