Noticed because a localizer was asking how to trigger them.

Bug 1474285 removed the section but didn't remove the strings.

separate-profile-mode
use-firefox-sync
get-started-not-logged-in
get-started-configured

Removing them, since it's affecting also the Proton cleanup of Sync.

Backed out for causing bc failures in browser_quit_disabled

Backout link: https://hg.mozilla.org/integration/autoland/rev/6ee7daf9a461d51c9ef7b70e177074d2e568f30f

Push with failures: https://treeherder.mozilla.org/jobs?repo=autoland&resultStatus=testfailed%2Cbusted%2Cexception%2Crunning%2Cpending%2Crunnable&fromchange=0abd3454600de062e5dca4140a71de592534a8c8&searchStr=OS%2CX%2C10.14%2CWebRender%2Copt%2CMochitests%2Ctest-macosx1014-64-qr%2Fopt-mochitest-browser-chrome-e10s%2Cbc1&tochange=f1e025de3da2e4c3820722ad301f6896f30c135a&selectedTaskRun=HQ2u2lAeSL-Gz3hMHoSJjg.0

Failure log:https://treeherder.mozilla.org/logviewer?job_id=329988007&repo=autoland&lineNumber=6049

"INFO - TEST-START | browser/components/tests/browser/browser_quit_disabled.js
[task 2021-02-15T11:40:27.196Z] 11:40:27 INFO - TEST-INFO | started process screencapture
[task 2021-02-15T11:40:27.247Z] 11:40:27 INFO - TEST-INFO | screencapture: exit 0
[task 2021-02-15T11:40:27.247Z] 11:40:27 INFO - Buffered messages logged at 11:40:26
[task 2021-02-15T11:40:27.247Z] 11:40:27 INFO - Entering test bound test_appMenu_quit_disabled
[task 2021-02-15T11:40:27.248Z] 11:40:27 INFO - TEST-PASS | browser/components/tests/browser/browser_quit_disabled.js | No quit button with shortcut key -
[task 2021-02-15T11:40:27.248Z] 11:40:27 INFO - Leaving test bound test_appMenu_quit_disabled
[task 2021-02-15T11:40:27.248Z] 11:40:27 INFO - Entering test bound test_quit_shortcut_disabled
[task 2021-02-15T11:40:27.248Z] 11:40:27 INFO - Buffered messages finished
[task 2021-02-15T11:40:27.248Z] 11:40:27 INFO - TEST-UNEXPECTED-FAIL | browser/components/tests/browser/browser_quit_disabled.js | Expected quit state - Got false, expected true
[task 2021-02-15T11:40:27.248Z] 11:40:27 INFO - Stack trace:
[task 2021-02-15T11:40:27.248Z] 11:40:27 INFO - chrome://mochikit/content/browser-test.js:test_is:1351
[task 2021-02-15T11:40:27.248Z] 11:40:27 INFO - chrome://mochitests/content/browser/browser/components/tests/browser/browser_quit_disabled.js:testQuitShortcut:52
[task 2021-02-15T11:40:27.562Z] 11:40:27 INFO - TEST-PASS | browser/components/tests/browser/browser_quit_disabled.js | Expected quit state -
[task 2021-02-15T11:40:27.562Z] 11:40:27 INFO - Leaving test bound test_quit_shortcut_disabled
[task 2021-02-15T11:40:27.562Z] 11:40:27 INFO - GECKO(1852) | MEMORY STAT | vsize 7053MB | residentFast 334MB | heapAllocated 154MB
[task 2021-02-15T11:40:27.563Z] 11:40:27 INFO - TEST-OK | browser/components/tests/browser/browser_quit_disabled.js | took 1405ms
[task 2021-02-15T11:40:27.565Z] 11:40:27 INFO - checking window state
[task 2021-02-15T11:40:27.670Z] 11:40:27 INFO - TEST-START | browser/components/tests/browser/browser_startup_homepage.js"

Per discussion on Element, this was backed out by mistake.

Backed out by mistake. Relanded the backed out patch. Sorry for the trouble

https://hg.mozilla.org/mozilla-central/rev/7abcfdd7ee54