fixup! Bug 40925: Implemented the Security Level component

Bug 42149: Do not change HTTPS-Only settings in the security level
anymore.

That preference does not really belong to the security level.

toolkit/components/securitylevel/SecurityLevel.sys.mjs

@@ -278,7 +278,6 @@ const kSecuritySettings = {
   "svg.disabled":                            [,  true,  false, false, false],
   "javascript.options.asmjs":                [,  false, false, false, true ],
   "javascript.options.wasm":                 [,  false, false, false, true ],
-  "dom.security.https_only_mode_send_http_background_request" : [,  false, false, false, true ],
 };
 /* eslint-enable */