fixup! Bug 30237: Add v3 onion services client authentication prompt

Bug 42667: Add the "description-deemphasized" class to our preferences.

Also use the "description-width-side-element" class.

browser/components/onionservices/content/authPreferences.css

@@ -2,10 +2,6 @@
 
 @import url("chrome://global/skin/browser-colors.css");
 
-#torOnionServiceKeys-overview-container {
-  margin-inline-end: 30px;
-}
-
 #onionservices-savedkeys-dialog {
   min-width: 45em;
 }

browser/components/onionservices/content/authPreferences.inc.xhtml

@@ -4,7 +4,10 @@
           data-category="panePrivacy" hidden="true">
   <label><html:h2 id="torOnionServiceKeys-header"/></label>
   <hbox>
-    <description id="torOnionServiceKeys-overview-container" flex="1">
+    <description
+      class="description-deemphasized description-with-side-element"
+      flex="1"
+    >
       <html:span id="torOnionServiceKeys-overview"
                  class="tail-with-learn-more"/>
       <label id="torOnionServiceKeys-learnMore" class="learnMore text-link"