Bug 942582 - [System] Improve string for emergency call back mode

Updated string by :matej
Bug 983117 - Disable intermittent failing test, Browser Bookmarks > Edit bookmark
Bug 983117 - Disable intermittent failing test, Browser Bookmarks > Add bookmark
Merge pull request #17148 from flodolo/bug942582_emergencycalltext

Bug 942582 - [System] Improve string for emergency call back mode