fix: type 'Null' is not a subtype of type 'bool'

E/flutter (10050): [ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: type 'Null' is not a subtype of type 'bool'
E/flutter (10050): #0      RendererPriorityPolicy.fromMap (package:flutter_inappwebview/src/types.dart:4598:38)
E/flutter (10050): pichillilorenzo#1      AndroidInAppWebViewOptions.fromMap (package:flutter_inappwebview/src/in_app_webview/android/in_app_webview_options.dart:422:61)
E/flutter (10050): pichillilorenzo#2      InAppWebViewGroupOptions.fromMap (package:flutter_inappwebview/src/in_app_webview/in_app_webview_options.dart:72:38)
E/flutter (10050): pichillilorenzo#3      InAppWebViewController.getOptions (package:flutter_inappwebview/src/in_app_webview/in_app_webview_controller.dart:1643:39)
E/flutter (10050): <asynchronous suspension>
E/flutter (10050): pichillilorenzo#4      _WebViewTabState._buildWebView.<anonymous closure> (package:flutter_browser/webview_tab.dart:158:39)
E/flutter (10050): <asynchronous suspension>

lib/src/types.dart

@@ -4595,7 +4595,7 @@ class RendererPriorityPolicy {
         ? RendererPriorityPolicy(
             rendererRequestedPriority:
                 RendererPriority.fromValue(map["rendererRequestedPriority"]),
-            waivedWhenNotVisible: map["waivedWhenNotVisible"])
+            waivedWhenNotVisible: map["waivedWhenNotVisible"] ?? false)
         : null;
   }
 }