chore: Remove remaining bits from zen rices, b=(no-bug), c=workspaces

src/browser/base/content/appmenu-viewcache-inc-xhtml.patch

@@ -1,15 +0,0 @@
-diff --git a/browser/base/content/appmenu-viewcache.inc.xhtml b/browser/base/content/appmenu-viewcache.inc.xhtml
-index 3c5c4f29b1de25a4ce17089502f2251a27e5c7f5..dfa3260ed3c2bb6067745696fbf103c7e56c639a 100644
---- a/browser/base/content/appmenu-viewcache.inc.xhtml
-+++ b/browser/base/content/appmenu-viewcache.inc.xhtml
-@@ -421,6 +421,10 @@
-                      class="subviewbutton"
-                      data-l10n-id="appmenu-customizetoolbar"
-                      command="cmd_CustomizeToolbars"/>
-+      <toolbarbutton id="appmenu-zen-share-rice"
-+        class="subviewbutton"
-+        data-l10n-id="appmenu-zen-share-rice"
-+        oncommand="gZenThemePicker.shareTheme()" />
-       <toolbarseparator/>
-       <html:h2 id="appmenu-developer-tools"
-           data-l10n-id="appmenu-developer-tools-subheader"

src/browser/themes/shared/zen-icons/icons.css

@@ -426,7 +426,6 @@
   list-style-image: url('customize.svg') !important;
 }
 
-#appmenu-zen-share-rice,
 #zen-copy-current-url-button {
   list-style-image: url('share.svg');
 }

src/zen/workspaces/ZenGradientGenerator.mjs

@@ -1307,18 +1307,6 @@
       return theme;
     }
 
-    get riceManager() {
-      if (!this._riceManager) {
-        this._riceManager = new window.ZenRiceManager();
-      }
-      return this._riceManager;
-    }
-
-    shareTheme() {
-      const manager = this.riceManager;
-      manager.openShareDialog();
-    }
-
     getNativeAccentColor() {
       return Services.prefs.getStringPref('zen.theme.accent-color');
     }