Show error message when screenshot fails

[moritz-suckow-mw]

Bug

Expected Behavior

WHEN

I make a screenshot of CodeCharta via the button for that and that fails

THEN

I want to see an error message, telling me what went wrong.

Actual Behavior

There is no output when an error is encountered.

Notes

The place to implement that is already marked with a comment in the file screenshotButton.component.ts