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- Fix for concurrency issue in taking and moving screenshots
- Updated BrowserHandler.take_screenshot so that it will store the name of the file that has been saved in a property
on the class itself.
- Updated BrowserHandler.move_screenshots_to_folder to take an optional parameter, file_names, that (if provided) will
override the default behaviour of moving all .png files from the source to the target folder, and instead will
only move files matching the file_names from the source to the target folder.