Add option to duplicate tab to window menu (#2663)

Task/Issue URL:
https://app.asana.com/0/1199230911884351/1207114296893342/f
Tech Design URL:
CC: @ayoy 

**Description**:
This PR adds the option to duplicate a tab to the window menu

**Steps to test this PR**:
1. Open a tab
2. Click window > duplicate tab
3. The current tab should be duplicated, if the tab is pinned the
duplicated tab should also be pinned.

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###### Internal references:
[Pull Request Review
Checklist](https://app.asana.com/0/1202500774821704/1203764234894239/f)
[Software Engineering
Expectations](https://app.asana.com/0/59792373528535/199064865822552)
[Technical Design
Template](https://app.asana.com/0/59792373528535/184709971311943)
[Pull Request
Documentation](https://app.asana.com/0/1202500774821704/1204012835277482/f)

DuckDuckGo/Menus/MainMenu.swift

@@ -319,6 +319,7 @@ import SubscriptionUI
                 NSMenuItem(title: UserText.zoom, action: #selector(NSWindow.performZoom))
                 NSMenuItem.separator()
 
+                NSMenuItem(title: UserText.duplicateTab, action: #selector(MainViewController.duplicateTab))
                 NSMenuItem(title: UserText.pinTab, action: #selector(MainViewController.pinOrUnpinTab))
                 NSMenuItem(title: UserText.moveTabToNewWindow, action: #selector(MainViewController.moveTabToNewWindow))
                 NSMenuItem(title: UserText.mainMenuWindowMergeAllWindows, action: #selector(NSWindow.mergeAllWindows))

DuckDuckGo/Menus/MainMenuActions.swift

@@ -601,6 +601,12 @@ extension MainViewController {
         WindowsManager.openNewWindow(with: tab)
     }
 
+    @objc func duplicateTab(_ sender: Any?) {
+        guard let (_, index) = getActiveTabAndIndex() else { return }
+
+        tabCollectionViewModel.duplicateTab(at: index)
+    }
+
     @objc func pinOrUnpinTab(_ sender: Any?) {
         guard let (_, selectedTabIndex) = getActiveTabAndIndex() else { return }