Bugfix FXIOS-8940 Re-add screenshot code (#19760) (#19763)

(cherry picked from commit 20c6074)

Co-authored-by: OrlaM <omitchell@mozilla.com>

firefox-ios/Client/Frontend/Browser/BrowserViewController/Views/BrowserViewController.swift

@@ -1764,14 +1764,28 @@ class BrowserViewController: UIViewController,
         }
 
         if webViewStatus == .finishedNavigation {
-            if tab !== tabManager.selectedTab, let webView = tab.webView {
+            if tab !== tabManager.selectedTab,
+                let webView = tab.webView,
+                tab.screenshot == nil {
                 // To Screenshot a tab that is hidden we must add the webView,
                 // then wait enough time for the webview to render.
                 webView.frame = contentContainer.frame
                 view.insertSubview(webView, at: 0)
                 // This is kind of a hacky fix for Bug 1476637 to prevent webpages from focusing the
                 // touch-screen keyboard from the background even though they shouldn't be able to.
                 webView.resignFirstResponder()
+
+                // We need a better way of identifying when webviews are finished rendering
+                // There are cases in which the page will still show a loading animation or nothing
+                // when the screenshot is being taken, depending on internet connection
+                // Issue created: https://github.com/mozilla-mobile/firefox-ios/issues/7003
+                let delayedTimeInterval = DispatchTimeInterval.milliseconds(500)
+                DispatchQueue.main.asyncAfter(deadline: .now() + delayedTimeInterval) {
+                    self.screenshotHelper.takeScreenshot(tab)
+                    if webView.superview == self.view {
+                        webView.removeFromSuperview()
+                    }
+                }
             }
         }
     }