Remove the default screenshot from the new bug form

[munteanu210]

On the current website, if a screenshot exists, the site shows the preview. If there is no screenshot, the site lets the users upload one. A few updates are needed to keep the functionality on the new bug form as it exists on the current website:

1. Remove the default / sample screenshot which came with the new design;

2. Keep the screen asking the user to upload a screenshot;

3. Keep the screen confirming that screenshot was uploaded;

4. Remove the word "automatic" on the screen which appears after deleting an uploaded screenshot.