no-bug: Fixed opening new private windows removing initial tabs (gh-13687)

src/zen/spaces/ZenSpaceManager.mjs

@@ -811,6 +811,7 @@ class nsZenWorkspaces {
       delete this._tabToSelect;
       delete this._tabToRemoveForEmpty;
       delete this._shouldOverrideTabs;
+      delete this._initialTab;
       resolveSelectPromise();
     };
 
@@ -874,15 +875,6 @@ class nsZenWorkspaces {
     }
 
     await selectPromise;
-    if (this._initialTab) {
-      this.selectEmptyTab();
-      this._removedByStartupPage = true;
-      gBrowser.removeTab(this._initialTab, {
-        skipSessionStore: true,
-      });
-      delete this._initialTab;
-    }
-
     const openOnStartup = Services.prefs.getBoolPref(
       "zen.urlbar.open-on-startup",
       true