Update QSE on default search engine changed

[deeppandya]

This issue is match the behaviour for quick search engines with IOS for default search engines.

• Default search should not be able to disable/reorder default SE in quick search settings. (We need to hide the default search engine from QSE settings, similar to IOS)
• Default SE should appear right after Leo in quick search engines view when user changes the default search engine from settings
• Default SE should always appear as 2nd item quick search engines view