Show error message when screenshot fails

# 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`

Start in screenshotButton.component.ts, where the issue says an implementation comment already marks the relevant location. Trace the screenshot failure path and add visible error output describing what went wrong; done means a failed screenshot no longer produces silent behavior.

Written by the indexing model from the issue text.