[Feature Request]: Option in preview mode

### What would you like to happen?

In preview mode, there would be an option to prevent any output insertions or updates to databases or writing to files. This would provide real usability for the preview. Today I see that the option itself is not used for this reason, since I am forced to uncheck the HOP output options.

### Issue Priority

Priority: 3

### Issue Component

Component: Hop Gui

Start by tracing preview mode in the Hop GUI and how output options invoke database updates or file writes. Identify the paths that handle preview execution, then verify that enabling the new option suppresses those writes without manually disabling each output option.

Written by the indexing model from the issue text.