fix: Fixed empty windows appearing when using the window.open JS API, b=closes #8958, c=workspaces

Author: mr-cheffy

src/browser/components/tabbrowser/content/tabbrowser-js.patch

@@ -1,5 +1,5 @@
 diff --git a/browser/components/tabbrowser/content/tabbrowser.js b/browser/components/tabbrowser/content/tabbrowser.js
-index d5aa64842a35c6697263c63fd3a0571b64b01344..031b384c848fd391f84ed1e6d4f991f3287e37a4 100644
+index d5aa64842a35c6697263c63fd3a0571b64b01344..48d8465f1a4d593ec6d4bff2bd7a83f44116506b 100644
 --- a/browser/components/tabbrowser/content/tabbrowser.js
 +++ b/browser/components/tabbrowser/content/tabbrowser.js
 @@ -413,11 +413,41 @@
@@ -357,7 +357,7 @@ index d5aa64842a35c6697263c63fd3a0571b64b01344..031b384c848fd391f84ed1e6d4f991f3
        // to remove the old selected tab.
        if (tabToSelect) {
          let leftoverTab = this.selectedTab;
-+        if (this._hasAlreadyInitializedZenSessionStore) {
++        if (this._hasAlreadyInitializedZenSessionStore || !gZenWorkspaces.workspaceEnabled) {
          this.selectedTab = tabToSelect;
          this.removeTab(leftoverTab);
 +        } else {

src/zen/workspaces/ZenWorkspaces.mjs

@@ -913,7 +913,7 @@ var gZenWorkspaces = new (class extends ZenMultiWindowFeature {
   }
 
   async selectStartPage() {
-    if (gZenUIManager.testingEnabled || !this.workspaceEnabled) {
+    if (!this.workspaceEnabled) {
       return;
     }
     await this.promiseInitialized;
@@ -1015,7 +1015,7 @@ var gZenWorkspaces = new (class extends ZenMultiWindowFeature {
   }
 
   handleInitialTab(tab, isEmpty) {
-    if (gZenUIManager.testingEnabled) {
+    if (gZenUIManager.testingEnabled || !this.workspaceEnabled) {
       return;
     }
     // note: We cant access `gZenVerticalTabsManager._canReplaceNewTab` this early