Reliability and other improvements

Reliability and other improvements

• Improve reliability of self.click_nth_visible_element(...)
• Improve reliability of self.set_value(...)
• Keep self._print(...) from printing during multithreaded runs:
  -- (Prevent garbled text on the console output)
• Update Python dependencies:
  -- pip>=21.2.1;python_version>="3.6"
  -- platformdirs==2.2.0;python_version>="3.6"