Extend the coverage of ui element checks for localization tests

tst_localization should check besides the login message text other ui elements, because ui elements populate from 4 different sources.

sources include:

• installer extensions
• server
• IFW sources
• license manager

Elements that needs to be checked:

• "Log in to Qt account" above the email input box

• "The Qt account will give you access...." below the "Sign up" link

• "Installation folder" in installer sidebar

• progress texts like "logging in" etc that appear below the progress bar when logging in from login screen <-- would be problematic to check, so skip this time.