Reliability and other improvements

Reliability and other improvements

• Improve Demo Mode reliability on sites with restrictive CSPs.
• Improve Safari reliability on the self.open_new_window() method.
• Update default driver versions used and displayed:
  -- Use Edgedriver "89.0.774.54" if cannot detect LATEST_STABLE
  -- Use Operadriver "v.88.0.4324.104" as the default version
• Improve self.assert_downloaded_file(file).
• When reusing a session, only keep the first tab/window open.
• Update Python dependencies:
  -- setuptools-scm==5.0.2;python_version<"3.6"
  -- setuptools-scm>=6.0.1;python_version>="3.6"
  -- Drop allure-pytest from installed dependencies