"Copy contents" button should not be shown if a rendering error occurs on Snippet
When a snippet's blob returns a rendering error (collapsed, too large, or store externally) we should hide the "Copy file contents" button as the content is not fetched by default in these scenarios.
However, in case of collapsed, when the user explicitly clicks "load it anyway" link, the button should be visible again.
Edited by Denys Mishunov