Bug 1827730 - Don't specify the cookie banner reduction panel header in the markup and let it be created by PanelMultiView.jsm r=emilio

Specifically, here:
https://searchfox.org/mozilla-central/rev/ad732108b073742d7324f998c085f459674a6846/browser/components/customizableui/PanelMultiView.jsm#1403-1457

Differential Revision: https://phabricator.services.mozilla.com/D175286

Author: ItielMaN

browser/components/controlcenter/content/protectionsPanel.inc.xhtml

@@ -402,18 +402,6 @@
                class="PanelUI-subView"
                role="document"
                data-l10n-id="protections-panel-cookie-banner-view-title">
-        <box class="panel-header">
-          <toolbarbutton class="subviewbutton subviewbutton-iconic subviewbutton-back"
-                         data-l10n-id="protections-panel-cookie-banner-view-go-back"
-                         closemenu="none"
-                         tabindex="0"
-                         oncommand="gProtectionsHandler._protectionsPopupMultiView.goBack();">
-            <image class="toolbarbutton-icon"></image>
-            <label class="toolbarbutton-text" crop="right" flex="1"></label>
-          </toolbarbutton>
-          <h1><span data-l10n-id="protections-panel-cookie-banner-handling-header"></span></h1>
-        </box>
-        <toolbarseparator />
         <vbox id="protections-popup-cookieBannerView-heading"
               class="protections-popup-description protections-popup-cookiesView-list-section">
           <description id="cookieBannerView-disable-site" data-l10n-id="protections-panel-cookie-banner-view-turn-off-for-site" data-l10n-args='{"host":""}'></description>

browser/locales/en-US/browser/protectionsPanel.ftl

@@ -121,8 +121,6 @@ protections-panel-cookie-banner-handling-undetected = Site currently not support
 
 protections-panel-cookie-banner-view-title =
   .title = Cookie Banner Reduction
-protections-panel-cookie-banner-view-go-back =
-  .aria-label = Back
 # Variables
 #  $host (String): the hostname of the site that is being displayed.
 protections-panel-cookie-banner-view-turn-off-for-site = Turn off Cookie Banner Reduction for { $host }?