Bug 1034082 - Update locators in Settings app
Bug 990537 - [DSDS] Messaging. Apply Visual Refresh to DSDS scenarios r=schung

* use :before instead of :after so that we re not affected by building blocks
* add the sim indication back
* use the correct style for the sim indication
* move the dsds CSS to composer.css
* correctly center the counter and MMS indicators
Merge pull request #21351 from viorelaioia/bug_1034082

Bug 1034082 - Update locators in Settings app
Bug 1027471 - [LockScreen][System] Split notification.js into LockScreen and System parts